Why not take a page from the Yacy p2p search engine of an optional blacklist client side to take care of stuff like this?

Kind of envisioning something like a hosts file level of blocking. Essentially proposing a strengthened mute feature where your client talks to the relay and makes the note undeliverable from the spammer and is unable to comment on your note. Not sure if this would be possible, but maybe someone with more knowledge can figure out something like this and make it happen?

https://github.com/yacy/yacy_search_server/blob/master/defaults/yacy.network.readme