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?
(For my part, I’m working on setting up my own Lemmy and/or Pixelfed instance(s) and I do not currently intend to defederate.)
Meta are performing what is called an EEE attack (Embrace, Extend, Extinguish). Basically, it involves a larger corporation creating a thing that hooks into an open standard, artificially inflating it, slowly adding new, proprietary closed-source features that other members of the open standard cannot use, and eventually removing support for the open standard entirely, forcing other users to enter their walled garden because that’s where all the people are. https://en.wikipedia.org/wiki/Embrace,_extend,_and_extinguish