Threads exists for the sole purpose of capturing some of the people showing interest in the fediverse as twitter dies and keeping them in the facebook ecosystem. Once it believes it has exhausted this window of opportunity it will defederate just as it de-federated it's xmmp based messenger service once it thought it had the upperhand.

Every server that defederates from meta preemptively is working to build a resilient community that will survive this inevitable scenario. Every server that federates with meta will become dependent on it then collapse as their users leave to join threads once that becomes their only option to continue interacting with the threads users that their social experience was built on.

Your post only concerns threats to an individual user re scraping or malicious interactions. The threat meta poses to the fediverse is systemic. In the long run the meta-blocking servers are the fediverse. The meta-federating servers might see some short term attention but in the long run will have the same fate as those that hitched their wagons to the metaverse.