I agree. She sued them a few days ago over it, and reiterates a couple of the worst claims in her complaint, so presumably over the course of that case the two sides will try to prove or disprove them. (It shouldn't be too surprising that Meta didn't start a court battle earlier - is there a single person on the planet who would read "Meta Platforms files $10 million defamation suit against whistleblower" and become less angry at Meta?)