Meta just announced that they are trying to integrate Threads with ActivityPub (Mastodon, Lemmy, etc.). We need to defederate them if we want to avoid them pushing their crap into fediverse.
If you’re a server admin, please defederate Meta’s domain “threads.net”
If you don’t run your own server, please ask your server admin to defederate “threads.net”.
You’re confusing defederation with Lemmy’s instance blocking. Defederation means that none of a server’s content is federated. Lemmy’s new instance blocking feature, however, only blocks communities and not users.