Hacker News itself is heavily moderated: spaces for expression are a commons, and people who abuse those spaces make them less useful for others, until they have infected the entire space making it only amenable to their sort of expression.
There's no such abstract ideal of free speech that transcends its legal definition. Speech is not neutral. If speech were neutral, it would not be so important. Since speech has effects, like harassing speech forcing people off platforms for expression, everyone has a shared interest in the expressive platforms they use. If an ideal of free speech precluded the moderation of conflicts arising from speech, what does it actually mean? That the most aggressive, vicious speakers get to monopolize the spaces they force others out of?
Re: Tolerance