Post history On: You get to follow a users comment history. If you read an insightful comment by them, and want to read more, then having a history is nice. Users are people
Post history partially On: e.g. comments could decay to anon after some period. (Cue the sites that collect all post data and match to users) Slightly increases the cost of doing a deep dive on a users history. Users are people, fading to ideas
Post history Off: Lowered attack surface for people who are actively trying to find an argument with you. Less pressure to have a persona consistent with the typical one of any particular community. Users are ideas
For example you can make multiple identities easier. I make use of that here via firefox containers, it is quite nice.
You can make anonymous the default and track the user under the hood, allowing them to claim a post at a later point if they feel confident enough to attach their name to it.
You could limit who can see the user identity. Or only display something more vague than a specific identity, a profile-lite behind a one-time ID.
4chan also exists and it works and is marvelously non-toxic once you realize that any insults hurled at you are impersonal because they can only attack what you have immediately posted previously. Your attack surface is tiny, assuming basic information hygiene.