Introduction

Two really good discussions on the subject I found are these two led by Claire Fox, a prominent British writer and politician, a former Marxist whose views gradually evolved into something approximating libertarianism:

https://www.youtube.com/watch?v=-TqrahnSJCs
https://www.youtube.com/watch?v=mJZqKKFn3Hk

The first gives an introduction into the phenomenon and description of its various aspects, and the second provides a wider outlook on the changes in the Western civilisation over the last couple of centuries that made the cultural shift in question possible.

Briefly, the "offence culture" can be characterised by the prevalence of the moral component of public discourse over its intellectual component. Rather than addressing controversial subjects, the "offence culture" demands that the discussion be silenced, lest it makes some people uncomfortable. And there really is no limit to where sufficient degree of controversy begins; there have been absolutely horrifying incidents, such as a teenage girl subjected to a massive bullying campaign over wearing a Chinese costume on a Halloween event while not herself being Chinese - some people found it offensive, and others followed the notion and joined in the bullying. It is a new type of censorship, which is fairly common in more authoritarian cultures, but is fairly unprecedented in the Western culture until very recently.
I would also characterise this phenomenon as triumph of emotions over truth. By the enlightenment doctrine, that made the Western secular civilisation based on supremacy of individual values over collectivist ones, truth is supreme and is the the ultimate goal of any intellectual activity. But by the doctrine of the "offence culture", the need for truth is secondary to the need for personal comfort, and if some harsh truth makes a lot of people uncomfortable, then it should not be talked about.

Rather than offering yet another rant on the Internet about the dangers of political correctness going too far or people having become too sensitive and weak-willed, I will propose an alternative take on this phenomenon. Rather than vilifying the phenomenon and the people who champion it, I want to suggest a more neutral and blame-free version of how this phenomenon came to be, why it finds so much support in the modern society, and why I think that its days are numbered.

Historical background

"Soft censorship" of controversial ideas goes far back, to the ancient times when religion was the framework upon which all further ideological constructions were built. The notion of some entity being "sacred" traces back, at least, to the Sumer times. Sacred entities were assumed to be connected to the divine and hence constituting the absolute and unquestionable truth, and any transgression from accepting that truth was punishable by societal ostracision at best, and by governmental or clerical persecution at worst.
There is no single explanation for how the concept of "sacred" came to be originally; the most plausible explanation I have heard from a historian was the need for societal stability at the early stages of human civilisation, the solution to which was found in attributing the leader of the community connection to the divine (which made his/her authority unquestionable, hence preventing power struggles putting the entire community in danger). In turn, that leader then would form a group of trusted advisors (who would later become clergy) who could declare certain entities as sacred, hence forming primal legal systems, with the advisors acting as both legislators and enforcers.

The concept of "sacred" is very convenient for power groups to use to subdue the population. Virtually all political and societal dissent can be nullified by getting the population as a whole to accept said dissent as "sacrilege". Such usage of the concept of "sacred" reached its peak in the Western world during the Medieval times, when the powerful clergy class kept the entire continent in fear and even effectively controlled monarchs.

By the 17th century numerous scientific discoveries, weakening of the aristocratic class and wider recognition of the rights of commoners loosened the clergy's hold on the European continent. The concept of "sacred" slowly gave way to the concept of "truth", dependent only on the fundamental structure of reality and not on any ideological doctrines. This ultimately gave way to the dawn of the Age of Enlightenment at the beginning of the 18th century, when people started questioning traditional ideologies and societal structures in favor of scientific method and abstract philosophy.
This led to evolution of religions themselves, as more value was given to free will and individual happiness, and less to collective interest and divine entities. This ultimately led to the American Revolution, which led to creation of the US, the first nation in the history of mankind officially proclaiming the supremacy of the individual freedoms and ideological pluralism over traditional collectivist structures. This triggered the wave of change throughout the entire Western world, and to this day we reap the benefits of that change.

Something happened in the 19th century, however. Rapid technological industrialisation, for the first time in human history, let to the world in which common workers could relatively easily sustain themselves materially. As the numbers of workers who could afford more than just some basic housing and food grew, it soon became obvious that there had been no discussion in the society on the interests of commoners. Philosophers struggled to offer a compelling narrative that would appeal to common people, who were still mostly fairly uneducated and could not parse complex logical arguments. People who finally could afford to travel around, to accumulate some material wealth and to negotiate terms with their employers on equal grounds, felt lost and directionless. They desperately needed someone to speak for them.
Unfortunately, the first group of philosophers who found common language with them turned out to be deontologists, such as Kant. Deontologists believe that quality of human action is characterised not by its consequences, but by its intent. This appealed strongly to the commoners, as they were given a clear instruction for how to make choices in life, and they did not have to go into complicated analysis of consequences of their action. As long as they had a goal and acted in a way that seemed aligned with that goal, their action was good and just.
It was a step back from the accomplishments of the Era of Enlightenment, which promoted the search for truth. To deontologists, truth was secondary to the intent, and could often even be sacrificed altogether in exchange for moral considerations.

Deontologist victory in the public debate ultimately led to the Marx' socialist ideas, who forewent the analysis of consequences of the proposed ideology in favor of it having noble goals. We all know what this resulted in in the 20th century: pools of blood all over the world, endless wars, nuclear threats and unimaginable suffering of hundreds millions people across the planet under ruthless totalitarian regimes. We are mostly past those horrors nowadays, but it would be naive to assume that they cannot make a comeback relatively soon. Ideological shifts are unpredictable and have a very strong influence on the historical process. But I digress.

What I want to bring your attention to is that deontologism still remains the main philosophical approach in the modern world, on the West and elsewhere alike. Consequentialism (which is the opposite of deontologism, and is the one professed by the Enlightenment movement) did make a comeback throughout the 20th century (mainly I would say because the opponent of the Western civilisation throughout the century was a totalitarian regime based on a deontologist ideology), but never quite made it to the top.
We see that nowadays, with Soviet Union gone and no comparable replacement in place, consequentialism once again is rapidly losing ground. The interests of commoners - and simple steps (even if disfunctional) offered towards fulfilling them - are once again the central topic of the public discussion, and the concept of "sacred" is making a comeback in the face of political correctness, resulting ultimately in emergence of the "offence culture".

Offence culture

So what is the "offence culture" exactly? Recall that religion and the concept of "sacred" emerged as a response to the societal need of stability. If, instead of working together for the common good, primal societies instead fought endlessly over their fundamental values, then everyone died to hunger, to wild animals or fell to other, more united societies.
Nowadays, obviously, we are no longer in such a predicament. An individual with values strongly differing from those of the collective in a modern Western country can live a very happy and prosperous life, and mostly exercise their values with no real danger to their life or freedoms.

There is a flip side, however. As our lives become more and more stable and prosperous, our standards shift. What yesterday was an unimaginable luxury, tomorrow becomes a necessity. Yesterday we were shocked that one can make a phone call from a phone station and talk to someone thousands miles away; nowadays we become frustrated over losing Internet connection for a few seconds, interrupting our Skype conference with 10 different people from all over the world, which we are having in our comfy apartment with a cup of hot coffee.
Our standards of comfort are also changing. We no longer have to suffer through going hungry for days, or having to work in a coal mine 100 hours a week. Hence we become uncomfortable with smaller things. And since arguably the most essential part of every human's life is interaction with other human beings, we become uncomfortable with everything that jeopardises that interaction.
This leads to us seeking refuge from having to deal with people and their words that make us uncomfortable. We close ourselves in our echo-chambers, where we only interact with like-minded individuals and do not have to face a lot of disagreements. But it does not end there: again, as we become comfortable in those echo-chambers, we start noticing digressions from common values even there, and the most charismatic of us start hijacking the echo-chambers and, in a way, radicalising them, where no dissent, however minor, is allowed. And as this process continues, we become caught in the loop of constantly looking for transgressions from the views we hold dear, as well as for transgressions in our own views from those of the group we associate with.

This is where the explanation of this phenomenon usually ends: "People have become too comfortable and sensitive". However, I think there is another development that, arguably, is responsible for the processes in question.
In the second discussion I linked in the Introduction, the speakers point out something interesting: the idea that people's search for the meaning of their life has become increasingly difficult. This is also something that psychologist Jordan Peterson points out regularly: that young people nowadays do not have the sense of direction in their lives; they do not know what they live for and what they want from life, and the education system, as well as the society as a whole, do not really address this problem.
In the Age of Enlightenment, this problem did not exist to this extent. The majority of people still barely made by and did not have either time or energy to ponder the big questions such as life's meaning and purpose: they just went to work, came back, went to bed and hoped that the next day they would get an hour of break to be able to do some housework. And those finding themselves in a more privileged position knew the answer, as the doctrine of Enlightenment was centered at it: the purpose of life, obviously, is to uncover the truth about the world through rigorous logical and scientific search.

Deontologism suggests that the intent matters more than the consequences. But what should the intent be? Nobody knows. But the property of human brain is that it always tries to fill the gaps in our knowledge with something that seems to make sense. Young people want to make an impact on the world, they want to do something that makes them fill fulfilled and acknowledged - so what should they do? The simplest thing they can do is activism, but what should they demonstrate about?
Western culture has been heavily influenced (I would even say "perverted") by Christian values, and those values have never really disappeared, albeit their influence has arguably diminished some. One of the core values is the collectivist idea of altruism: that helping others should be the goal of one's life. Now, there is nothing wrong with this idea in itself: one can hardly construct a moral system in which helping other people is wrong. However, with nothing else to do, the people desperately searching for a purpose jump onto this idea and, with maximalism naturally arising from desperation, take the idea to its logical extreme.
The Western civilisation has solved virtually all major problems we had up until the 20th century. Hence people who want to help others no longer have very clear venues on how to do that. Sure, one can help the homeless directly, or do some volunteer work at a local hospital - but people want to make a bigger impact than that. And so they instead start championing the ideas of equality and justice on the national, or even international, scale. And, again, they take these ideas to their logical extreme.

What comes from the mind of a person who sees a photo of a non-Chinese girl in a Chinese costume on the Instagram and decides, "This is unacceptable. I need to tell this girl that she is an irredeemable racist"? I will not pretend to be able to read the minds of others, but my guess is that the train of thought is approximately the following: "I feel empty and want to do something that makes a difference. Yet I am just clicking on pictures on Instagram aimlessly. Can I do something here? Okay, this girl is wearing a Chinese costume, but what does she really know about the Chinese culture? I suppose I should point out how disrespectful it can be. Actually, to think of it, this is very racist and inconsiderate. In fact, I do not think this girl should be allowed to do something like this ever again..." - and it is clear that this leads in a very dark place.
You see this everywhere: people pick on completely insignificant issues and often even get it backwards. It is easy to think that those people are just intellectually deficient, or emotionally insane. Yet when you actually talk to those people, you can feel their pain, their frustration at life in which they cannot find their place.

I want to emphasise this: those people are NOT evil, or , or even just immature (although they are that too). What they really are is lost in the modern rapidly developing world, where nobody teaches them who to do about their lives, what goals to set, who to interact with and how. They are confused and look desperately for any possible direction, no matter what it is. And, of course, they find it in something that makes them feel good short-term, even if in the long run it makes them even more miserable and lost.

What to do about it?

It is hard to argue that the "offence culture" is only becoming more and more prevalent with time, and now a lot of these lost young people are even getting positions in the Western governments. They are gaining access to the legislative apparatus that will allow them to enforce the abysmal ideas the culture promotes, undermining the most fundamental principles of the Western culture and reverting to the totalitarian ideas of censorship and collective responsibility. 
The future appears pretty dark, and while we definitely should not expect anything akin to restoration of the 20th century totalitarianism, it is fairly certain that it will become more and more difficult for people to speak their genuine thoughts openly. The associated rise of identity politics, where people are judged not by their individual merit, but by the racial, gender, religious, ethnic, etc. group they belong to, can return us to the segregationist past, which will further divide the society and pit people against each other. Collapse of open communication in a society historically has usually been a vanguard of approaching tyranny, and it would be naive to assume that, just because we live in the most prosperous civilisation this planet has ever harboured, this cannot happen here.

At the same time, history is full of ups and downs. A similar phenomenon as we are witnessing nowadays has already flashed a couple of times in the past, mainly in the 1960-s, where people all over the world marched in support of disadvantaged groups and demanded massive governmental action against the advantaged groups - and those movements died out eventually. Will the "offence culture" on the West die out as well in the nearest future? A group of unexpected anti-establishment election results all over the Western world in 2016-2018 shows that a large fraction of the Western population acknowledges the problem, and while their solution to the problem may be misplaced, it is good to, at least, have someone do something about it.

I also put my hopes in the effects of the technological evolution. A large part of the problem is lack of open communication between various groups of people and the resulting formation of echo-chambers. However, communication between people from all over the world becomes more and more seemless, and yesterday's rivals today can randomly meet in the online space, have a discussion and find that they actually have a lot more in common than they thought before.
With the emergence of decentralised currencies, cloud technology and neural networks, I project that people will become more and more self-reliant over time. They will be forced to confront the issues with collectivism in the context of the fragmentation of the society, and the answers they find will likely have less to do with championing the interests of specific groups of people, and more to do with championing some universal values applicable to all individuals.

I also think that the technological evolution will naturally shift the collective philosophical consciousness away from dentologism and towards consequentialism. Computers are, indubitably, the central part of modern people's lives, and computers are based on strict binary logic which is only compatible with consequentialism: either the program you wrote runs, or it does not, and your intentions are absolutely irrelevant as to the outcome. Dentologism cannot survive binary logic.

For now, the best we can do is to stay true to our ideals, to speak our minds however hard it may become in the future, and have conversations with people who want to silence us. It is important to not vilify them and consider them beneath us, but to understand where they are coming from, what issues cause them to want to silence those whose words upset them - and why those words upset them in the first place. In my experience, a lot of common ground can be found even with the most vocal "offence culture" practitioner, but you must be willing to endure a barrage of attacks before they start listening to your points. I again cannot help but bring up Jordan Peterson: in interviews with him you can see, pretty much, the perfect way to have discussions with those who do not want to have a discussion with you. Answer calmly and with dignity, never take anything personally and do not let the heat of the argument hijack your logical affinity - and even if your opponents do not accept your point for now, you will, at least, reach out to some people who will start thinking more about what you said. This is how the change is made: not by one sprint, but by continuous effort.
I do not propose that we all get involved in politics and spend an ungodly amount of time talking to people about these issues. However, we can stay true to our values in our everyday lives and never compromise out of the desire to avoid a backlash. This is the world we are going to live in for a long time, and it is important to not let it fall apart.

Final thoughts

I can understand how unpleasant the recent developments in the Western world may be to those of us who hold the fundamental Western values: individual freedoms, ideological pluralism, truth-seeking and equality of opportunity.

However, it is important to put things in perspective. Statistically, virtually everyone living in the developed world, a subset of which is the vast majority of the Western countries, is within the 10% of the most prosperous people on Earth, and within the 1% of the most prosperous people in the history of human civilisation. Such unbelievably high material wealth levels, such long life expectancies, such low crime rates, such wide social and economical opportunities and access to such amount of knowledge and people from all over the world - is something nobody could even dream of just several decades ago. Even now, as we complain about the gradual decay of Western values, the vast majority of people on Earth live in the conditions we would not wish on our worst enemy. We are having it unbelievably good, and we should never take what we have for granted.

As far as I am disappointed by the recent trends in the political correctness and the "offence culture", I am equally amazed by the number of people who choose to speak up and resist these trends. There are freedom of speech panels regularly held in the US and the UK, there are online groups from all over the world from people coming together and forming open discussion platforms (such as this website, where we discuss a large variety of controversial topics daily), and there seems to be a rise of classical liberal and libertarian political movements in the US, the UK, Switzerland, France and even such countries as Brazil or Argentina. People know what is at stake and respond accordingly.

I believe that, however grim the future in terms of free speech culture can seem now, we will get through this period of history successfully. We have gone through far worse just in the last century alone. While it may seem that the Western culture has eroded, it still features a lot of great thinkers, open discussion is still being held (even if somewhat constricted), and the backlash against the recent developments is impressive indeed. When videos of Jordan Peterson, Bret Weinstein or Christopher Hitchens on free speech are watched and upvoted by dozens millions, you know that we are still living in the civilisation in which truth is respected and sought, and as long as this is the case, authoritarianism will always be kept in check.