I still don't understand how the general public trusts anything Mark says. Investors, I understand, they only care about money, and perhaps rightfully so. But the community, why?

Where does the general public trust him? The general public uses Facebook to keep in touch with people or look at cat videos - and Facebook of course does whatever Mark wants. But I don't see how any trust between him and his users is involved.

I still don't understand how the general public trusts anything the media says or what the general public says...

Critical thinking is not what most of the population is taught.

Meta being Meta is nothing surprising. Why do people even bother using Instagram and Facebook?

Zuckerberg doesn't think he should be trusted. He thinks Meta users are dumb fucks for trusting him:

https://www.theregister.com/2010/05/14/facebook_trust_dumb/

Public opinion doesn’t matter anymore, thats why billionaires like him are building doomsday bunkers on remote islands.

Their plan is to watch the world burn.

He just doesn't seem particularly untrustworthy. I don't agree with his vision for humanity, but given the amount of money he's tossing at AI researchers, it seems clear that he genuinely believes it and is genuinely pursuing it.