It’s simply an expression. Meaning over time, all things added up and we’d be afraid to say and do anything for fear of some stupid thing that was said years ago. It catches up to people.Death of what? I would ask.
I have no problem believing that the off color jokes I may have laughed at in the 1970s were actually racist and have no place in today's culture. And if someone posts a stupid tweet when they are drunk or whatever, and it gets them fired, again, it's not the "end of civilization." I am simply not feeling threatened by those things or any of your other examples.
From where I sit, the most egregious example of cancel culture is the war on wokeism itself. And, sadly, the warriors appear to have no level of insight about that.
From where I sit, if people cannot admit to an obvious problem and try to do better, that’s a problem. Trying to block free speech that people don’t agree with, is a major problem. That festers into much bigger issues over time.