As far as I can tell, I can already do that on Lemmy. Not sure about Kbin. My own instance is linked with 486 other instances right now and Lemmy.ml is linked with 3577. Considering those numbers, I'd think manually whitelisting all of them would be a huge pain. So admins would be faced with a dilemma: whitelist and miss the point of the "Fediverse" or blacklist and give in to playing a never ending game of Whack-a-mole.
My best guess is there will be community-run blacklists that instances can automatically subscribe to in the future, similar to ad blockers, to make this part of instance administration less of a pain.
Yes, exactly. I don't know how email spam filters work. Looking up DNS RBL, I now understand it better. I agree, something similar to that would be more elegant and effective than something like ad blocker lists.
i suppose I could do that but honestly only like the Chat, Science, and Technology communities on beehaw. the rest of them are either too niche or just pointless