Just like every thing else, this too was amplified by the internet.
If you said something controversial 40 years ago at a grocery shop, shop owner might be mad and refuse to service you, and might even put a bad word for you across the town. In the worst and rarest case, you might have had to leave town.
Now, anyone can record the interaction, put it in front of more people on twitter than the front-page of a big newspaper. And this amplifies things. Not to mention that it remains there forever for the whole wide world.
At this point in many places, you will be more quickly forgiven for taking cash from a shop's register than saying something which is not the prevalent opinion.
It's not new. It was huge when religion was more prevalent, for example, but it was becoming less of a problem as society became more educated and secular. Now there's a new wave riding on top of social media like Twitter, and as it gains more popularity it's becoming more about flaming vs virtue signalling than making actual progress.
> but it was becoming less of a problem as society became more educated and secular
The last generation of control freaks had figured out how to use religion as a medium for their desires. They were caught flat-footed by new internet media like everyone else.
The next generation have now learned how to use twitter. The basic tactics probably haven't changed that much but the details of the message are new. I doubt education was a driving issue as this is more an issue of personality types.
We all can get caught up in to some degree. Some of the change is great, but the snowballing effect of social media leads to some mistakes that get easily out of hand. Education hasn't been able to adapt fast enough to technology and has left people unprepared for this sort of thing. It's not that it's a driving issue but it hasn't been of help when ideally it would have.
> It was huge when religion was more prevalent, for example, but it was becoming less of a problem as society became more educated and secular.
Secularism vs religion is a red herring. Society became freer because people began to value (classically) liberal ideals--i.e., people came to value freedom as a principle. Liberalism is secular but secularism isn't liberal (nor is it inherently illiberal), and there have been many illiberal secular ideologies not only in theory, but in practice (e.g., practical communism of the 20th century wherein people were literally executed, imprisoned, exiled, etc for their free speech). And of course what we see today.