A lot of people dislike it for the privacy nightmare that it is and the threat of an EEE attack. This will probably not be the last time that a big corporation will insert itself in the Fediverse.
People also say that it will help get ActivityPub and the Fediverse go more mainstream and say that corporations don’t have that much influence on the Fediverse since people are in control of their own servers.
What a lot of posts have in common is that they want some kind of action to be taken, whether it’d be mass defederating from Threads, or accept them in some way that does not harm the Fediverse as much.
What actions can we take to deal with Threads?
In a federated system, users on Alice can see and post into communities hosted on Bob, eg alice/c/funplace@bob. When Meta tries to join, Alice chooses not to federate - avoid giving meta free content, protect its users from ‘bad’ meta communities, preemptively block toxic meta users, whatever - but Bob does federate. Alice users can’t see meta/c/advertising, there’s no way to subscribe to Alice/c/advertising@meta. Both Alice and Meta users can see Bob/c/funplace, and so alice users can see anything that meta users post there and meta ‘gets’ any content that alice users contribute. Bob effectively acts like a tunnel between alice and meta users.