Have the admins of lemmy.world ever given a reason for this decision?
Yes. This post gives their thoughts around the time Threads started talking about federation and it’s pretty much “let’s wait and see if this results in problems”. They note a high probability of problems leading to defederation if a significant number of Threads users start posting to Lemmy communities.
I am happy with this approach. I want my Lemmy server to federate with every compatible server unless and until that server becomes a source of problems. I do not want it to preemptively or transitively[1] block anything. The great thing about federated systems is that people who are not happy with that approach can join a different server with policies that better match their preferences.
[1] A transitive block is blocking a server because it doesn’t block a third server.
otter@lemmy.ca 6 months ago
For what it’s worth, it doesn’t realistically change much since Lemmy (software) doesn’t federate with Threads in any meaningful way. The benefits are there, my understanding is that it’s mostly symbolic. This is also why you might see a lot of Mastodon instances staying federated with Threads, because there are tangible benefits and drawbacks to that decision.
As for WHY an instance is staying Federated, see some discussion from this other thread here: lemmy.ca/post/11771031
It’s not as simple as “that instance is a traitor”, and attacking other users/admins over this without considering the nuance is silly.