Comment by microtonal

There are exceptions, e.g. lobste.rs has an invitation tree. When someone starts posting LLM-generated comments, that part of the tree can get yanked. Also, it builds up a community gradually, because you need to be invited by someone. Since the invitation tree is visible, people will generally only vouch on people they trust, because an invitee that violates the rules will reflect bad on the inviter (and might get removed if they do that too often).