Wanting free speech on internet forums is different from wanting it at the government level. I'm not sure what Free Speech Absolutism is, but if it means unmoderated internet forums, yeah that usually doesn't end well even if only a small minority has bad intent.

Big online forums with any kind of global popularity already have an inherent problem despite the moderation, not because of hate speech but because of ragebait and other forms of grifting. Especially with anonymous users.