Your point about violence is a good one. I think it's a cultural thing when it comes to depictions of sex. And I think it has to do with the open internet being so easily accessible by children who shouldn't be exposed to sexual content. But it doesn't make any sense that they'd allow nude females but not nude males, unless the site is run by sexist males, which sounds like it might be.

It doesn't match the name "DeviantArt" either. Deviancy I would expect to be welcoming of many forms of art, but the fact is they aren't open. Censorship sucks, but the reality is these sites can do whatever they want and make up any rules they want, even if they're dumb ones.

I still think they are a leader. Many artists I see at artist alley's at anime conventions still tout their deviant art site links on their business cards. The professionals are more likely to link to their own site but many still maintain a DA account. Probably because it's good exposure for them.