Afaik, whenever an Activitypub instance has defederated from another it has always had to do with some combination of bad user behavior, poor moderation, and/or spam. Are the various instance admins who have decided to preemptively block threads.net simply convinced that these traits will be inevitable with it? Is it more of a symbolic move, because we all hate Meta? Or is the idea to just maintain a barrier (albeit a porous one) between us and the part of the Internet inhabited by our chuddy relatives?
If I wanted to use Facebook and subject myself to the community that includes, I’d use that. I prefer a less hostile/more thoughtful place, which Lemmy.world is to me. If Threads becomes accessible to Lemmy.world and brings that community within this sphere, I will very likely move on.