I agree that it's a loud minority complaining about Threads but that loud minority is quite powerful in the Mastodon community.

I think the "embrace, extend, and extinguish" fear is hilarious. The Fediverse is tiny and useless to Meta. Threads as a really crappy Twitter clone is just launched and many times the size of the Fediverse. By federating, they're losing algorithmic control and monetization possibilities. Honestly, I think it's just a "do good" afterthought for the sake of PR.