Meta are dominant in their sector across the globe. Of course they follow American standards, but their dominance insures the rest of the world goes by American standards.
Indeed there's no laws in the US that protect violent images whole covering the body, but that is the cultural standard which has been exported around the world.
I get that you're making a point that, why give control abroad to governments when I'm the US companies self censor?
First, what goes into the hands of companies versus the state also various culturally, and the US does have content laws other than the one you highlighted.
About the cultural standards, what would be normal in some other parts of the world? At least in the US, parents don't want porn showing up on kids' social media, and a sizeable number of adults at least don't want other people to see it on their screen. Big social media site like FB probably has to encode this as a "no nudity" rule.
I'm not sure about the violent images. There are definitely rules against showing bodily harm on FB, but I have no idea where the line is.
What would be normal? Like the poster above said, if my family goes to the beach and we take our shirts off, my girlfriend would be censored on Meta services but I wouldn't.
Notice that your comment equates nudity with pornography. Where I'm from it's not normal to do that.
I didn't equate nudity and pornography, and Americans don't do that. I'm asking if porn is normal elsewhere (answer was no) and saying FB moderation board might be lumping them together because there aren't fair ways to designate porn vs not.
If there's a social media site in some other country that doesn't have those rules, that'd be a good example.
As an aside, I don't know if there's any US law against showing adult nudity on a website. Maybe there's a rule about users being over 18.