Less violence, on the other hand, is a clearer goal that aligns with existing laws against violence, so it has a firmer basis, in line with existing restrictions on speech. It also gives you a non-partisan measuring stick.

Private platforms, on the other hand, will have more flexibility in trying to maintain, say, discussion quality as a goal (see HN's stated moderation goals vs Reddit's). Or disinformation, or language/profanity, or whatever else a private moderator may choose.

The government telling those private parties that they can't set their own standards, though, seems like a particularly terrible direction to go.