The comment control feature is protocol agnostic. In streams, there is an app called 'Comment Control'. Install it and you have full control of comments on every post. In Hubzilla, this is controlled in the permission dialogs, and I believe you can set comment controls for a channel, but not per-post as you can do with streams. We tend to share a lot of ideas between these two repositories so the newer control will probably show up on Hubzilla eventually.

Federation isn't really involved in comment control. If I don't want to see your comment, it is my divine right to refuse it or delete it. The only place federation is involved is to not provide a comment box if we know in advance that the comment is only going into the rubbish bin and save you typing a long reply into space.  

The zot/6 spec is under 'spec' in the Hubzilla repo and there are some implementation details of the ActivityPub implementation of comment controls in FEDERATION.md in the streams repository. We've since extended these to be at least partially compatible with FEP-5624 -- if you don't like the way we implemented it in 2012. Since nobody has shown any real interest in nomadic identity or working together on better permission controls on the fediverse (preferring to extinguish us instead), I haven't yet provided a spec for Nomad (which is basically Zot/11). The streams repository does include the only known reference implementation of Nomad.