On a wider scale, can't spell "ethics" with "business practices" anyway.
Back on topic, Threads is only a problem for the "All" feed of federated instances with users senselessly following people from Threads, while defederating won't stop Meta, or anyone, from syphoning and abusing any publicly available data from the Fediverse. Other than that, Meta's algorithms have no power here, the Fediverse isn't Meta's playground even if all instances federated with Threads.