Meta is a socially transmitted disease. There's no reason to "wait and see" with Meta, we already know them. Meta is not new, it's Facebook, with a new name and a fancy new logo to deflect attention away from all the terrible shit they do and have done, to individuals, groups, communities, and society as a whole.

So much terrible shit that unlike many Wikipedia articles that have a "controversy" section, Meta/Facebook has entire pages devoted to their terrible shit.

https://en.wikipedia.org/wiki/Criticism_of_Facebook

https://en.wikipedia.org/wiki/Facebook_content_management_controversies

https://en.wikipedia.org/wiki/Facebook_emotional_manipulation_experiment

https://en.wikipedia.org/wiki/Facebook%E2%80%93Cambridge_Analytica_data_scandal

There's more. Meta is not some new and exciting player in the ActivityPub field. They're a known quantity, and there's nothing to gained by allowing them to flood the Fediverse with low-quality shitposts at best, massive social manipulation campaigns at worst, and everything in between. In my humble opinion.