[foob]

This is absolutely the case. When I was in physics, I was told that the moderation policies had previously been more strict and were only relaxed after one of the quacks was rejected and murdered someone in retaliation. I don't know for certain whether that's true or an urban legend, but it was told to me by a physicist who would never joke or lie about something like that.

There's also viXra [1] which is like arXiv for fringe content that arXiv won't accept. One of the people who publishes there underwent a huge email spoofing campaign where they would send emails from one of my coworkers to others in the field promoting the papers. It was a really difficult situation because the coworker didn't know exactly who they were being sent to unless they replied, so it damaged his reputation without him getting a chance to explain what was happening.

[1] - https://vixra.org