Meta is not a person and Meta as a corporation (and the people who run it) are complicit in war crimes.
As for their users (which I am not conflating with Meta, the corporate entity), there is nothing stopping them from creating a Lemmy account.
Again, Meta is not a person and Meta is not it’s users. There is nothing wrong with many of the people who use Meta products.
Edited: I apologize, I removed part of the comment that was on retrospect, uncalled for.