I think it is overblown as a phrase, but there are loads of examples, especially on universities and in the mainstream media which is pretty intolerant of things it deems not polite.
So yeah, it is overblown but the people on here saying cancel culture doesn't exist is a bit like a load of white guys saying racism doesn't exist.
It does go on and people are definitely fearful of voicing their opinions in front of many 'liberals' in much the same way that others are in front of some conservatives, especially in the past. I have a friend at BBC radio Wales who strongly stated this was the case there. You just have to toe the line to the prevailing elite.
None of this is good and pretending it doesn't exist at all is daft