It is my genuine belief that presuming bad faith (as you have done here) is one of the most common antisocial behaviors that people don't even admit is antisocial. It is toxic to the civil exchange of ideas. It's even mentioned in the Hacker News Guidelines (https://news.ycombinator.com/newsguidelines.html): "Assume good faith."
The other antisocial behaviors mentioned in this article (animal cruelty, r/jailbait, etc) are certainly worse. But they are also committed by people who know that what they are doing is socially unacceptable. They know this but don't care.
When people presume bad faith, they often do so completely convinced that they are the good guys. I am sure I have fallen prey to this myself plenty of times.
But this is why the attitude is so dangerous: "Antisocial behavior is bad, and I know it when I see it. I can be trusted to identify what is acceptable, and who deserves a platform." Well, probably you notice it when you see it in other people. But we as humans are really good at rationalizing our own actions.
For the record, I completely agree that moderation is necessary to keep communities healthy. But I think it's harder than people think to apply moderation in a way that isn't just reinforcing the beliefs and taboos of whoever is in charge. For example, I see too many greyed-out comments on HN whose tone is the same as other highly-moderated comments. The only difference is the opinion being expressed.