I still don't see how things will exactly go bad for the existing instances by communicating with Meta instances.
The arguments in this article are "They won't moderate" and "Meta is evil". One is speculative, and one is biased... not convincing arguments to a neutral judge.
The drawback I see is that Meta communities will just be bigger and suck people out of the "nice" fediverse. But not federating with Meta won't change anything about it. If anything it causes harm because existing communities can't profit from the new Meta users joining.
Exactly. Why would facebook even care about the existing, tiny, fediverse? They are probably doing this because the infrastructure maybe makes sense somehow for geographic reasons to save on server costs.