I do not really understand all the fuss and fear about Threads.
Either the content is good, then we should be happy and federate.
Or it's bullshit/insults/racist/etc. crap - then we just block it.
Federation with threads could help threads to become the "default" home instance for most users. Then meta could pull the plug at any moment as most new communities would also run on threads. Threads could be the good old "Embrace, extend, and extinguish".
In reality, Meta is not federating to pull the few people off the Fediverse.
We are far too few to be of any relevance. Threads got twice the amount of users within a day. Soon they will dwarf the whole Fediverse even more.
The only reason why they announced to (and will) federate is to avoid anti trust problems.
And that also means: If they pull the plug and defederate, they will immediately end up on investigation.
All opinions are valid, and we can all choose instances that align with our views, but for my part I won't support an instance that federated with meta just on principle.