My objection with federating with Threads has nothing to do with privacy or data access, it has to do with keeping the ActivityPub protocol alive. Embrace, extend, extinguish is a much more legitimate threat to the fediverse than data scraping ever will be. No, the danger is that Meta will begin to contribute to the protocol. At first, contribution by a corporate actor would seem like a fantastic boon to an open standard that we wish to see grow, that's the embrace phase. But it would not be long before Meta began adding features that are exclusive to a Threads user - they'll extend the protocol to better accomplish their ends. In this way, they seek to bring more and more users into their platform in order to take advantage of these exclusive features while maintaining compatibility with the larger Fediverse. The end goal is to have enough users that when they decide to break that compatibility, they will make off with the majority of the users from the open community; that's the extinguish part.

This is a well-established strategy that large tech companies have employed with open standards in the past (see XMPP). I strongly believe it is in the Fediverse's long term interests to remain defederated from Threads, and any other large corporate player. Better to have fewer users and grow organically than to federate with Meta; we may see a short term boost to the fediverse, but the long term risks outweigh any benefit.

That being said, the nice thing about the fediverse is that I can just leave this instance for another if I disagree with the admin's decisions.