This critique of “user choice means that every instance should try and be as open as possible and try and federate with as many compatible entities as possible, so that any user, from any instance, might find and interact with content from everywhere” is as valid for instances blocking Threads as it is for blocking instances for allowing hate speech and bot-boosted corporate ads.

Personally, I prefer those to be blocked and have “user choice” mean users choosing to participate and promote the instances they believe are more useful, because my “user choice” is “I don’t want all kinds of bullshit to arrive unfiltered at my feed”.