You make a very good point about nudes as art or porn. I guess I wasn't thinking about this as a 'porn' site but as an 'art' site, but it could degenerate very quickly if 'anything' was allowed.
My wife and I had a large collage assemblage that was in a big show that was in 10 cities in the US and 4 cities in Japan many years ago. At no point was our piece censored as it had no nudity in it, however, in some cities and Japan nudes were pulled from the show and not displayed at all. It was very hurtful to artists who had loaned their works to the exhibition. The pieces were included in the catalog but not in all exhibits. I guess that is what I was thinking about. The show was '2 X Immortal: Elvis and Marilyn'.