There is nothing they can do to fuck up your experience, ESPECIALLY on Lemmy though. Threads is a completely different concept from Lemmy and activity pub is well defined.
The only thing they could do is just not moderate threads and therefore putting spam in everyone’s feeds. That’s about it. I don’t think they’re leaving that unmoderated.
They don’t get more data because they’re federated. They literally the exact same amount of data as they do know just by scraping mastodon or Lemmy. They’re an even player in this market. Somehow you all keep forgetting that. If you don’t want meta do have data from activity pub, you being here already violates that ideal.
This behavior is why the fediverse alienate users and makes it hostile for new people to join.
They didn’t do anything, yet. Give them the chance but start with 2 strikes on their account already. They fuck up, THEN you defederate. Innocent until proven otherwise.
Edit: go on, downvote me. Show me your face. Show me how you’re all against growth on Lemmy and niceness to each other.