I mean, I've seen plenty of dissenting material against the powers-that-be on Meta platforms over the years, but okay.

Police brutality (both viewpoints), COVID conspiracies, election conspiracies, etc. are not particularly hard to find on there.

Is posting about CEOs allowed there?

Yes? I've seen plenty of Facebook posts about how CEOs are greedy, criminal, ripping us all off, etc. I'm really not sure how you could have gotten the impression that it's not allowed to talk about CEOs on Facebook.