“They would now be denigrated as establishment elites.”
You used “now”, and you’re right. That was then, and this is now. Much has changed from 20 years ago.
The issue is less how some views have shifted, and more an intolerance of those who disagree with at least some aspects of that shift. And in a great many cases, the intolerance is deliberate -- a purposeful effort to drive from the site those who don't agree with a particular POV.
A push for extreme Trumpian orthodoxy necessarily leaves little room for actual discussion. Because if there is disagreement/discussion on something, then one of the two parties is necessarily varying from that orthodoxy. And that isn't permitted. So, either agree or leave. And if the only acceptable discussions are those in which everyone agrees, how interesting is that?