Threads has begun testing federation over ActivityPub. And they have blocked two important servers I administrate. The first server is the Mostr Bridge. The Mostr Bridge connects ActivityPub and Nostr together, so people can communicate across protocols. The second server is Spinster.xyz, which is arguably the largest independent feminist community online.
I think lemmygrad.ml is known for brigading. As for actual hate speech I think the instance this article is talking about is transphobic based on what others have said in this comment section.