I'm surprised legitimate companies don't pressure Facebook on this though. There are enough scams on Facebook that I now refuse to believe anything there, even though some of the things look useful and probably are not scams (and also are things I didn't know existed without an ad - thus filling one of the legitimate values of advertisements: informing me of things that would make my life better but I don't know exist).

Your first assertion is obviously untrue. And fake celebrity endorsements pre-date the existence of the Internet, let alone Meta. There were lawsuits back in the 1800s on this topic. This is hardly a new problem unique to Meta.