The fediverse, bikeshedding as it always has, forgot that the true failure model is the same as it always was, from Eris to Scientology: a bunch of script kiddies having a very, very loud slapfight.
Misskey.io's temporary solution is what I anticipated would happen for a while: an allowlist of instances - not even a blocklist, as not only can you not keep up with the pace of open-registration instances, they can just start spinning up new ones. It's the same problem e-mail has had for decades: spammers have an infinity of domains at their disposal.
