Its interesting to see how Twitter (and social media in general) transformed from something positive where you could find community within a large subset of people and then all patted each other on the back and it was really cool place to hang out but then it slowly became this cesspool of negativity. Twitter just let it happen and now we're at at a tipping point where you have to decide if you want the government to intervene and regulate, or simply let it slide into oblivion.
The even more interesting thing is all of the people I know and worked with in those early days fled Twitter for Mastondon. Now they're saying the same thing is already happening on that platform as well.
It is very self selecting though, isn't it? You even acknowledged that mentioning people fleeing Twitter for Mastodon. It seems Twitter (etc.) attracts the people who want to make a lot of noise without repercussions, who then proceed to make the most noise. And studying behavior on Twitter just studying this small subset of Twitter users, who are a even smaller subset of the general population. Or are you able to adjust for all this?