See I raise this question BECAUSE I don't understand why x is ok, why y is not etc. I'm not poking the wasp's nest, I'm trying to make sure I don't mess up.
A nude only forum would see next to no activity except on the miley Cyrus and Chelsea Handler threads both of whom regard clothing as redundant. If you want an active forum I don't see that as practical or even desirable by the majority of the membership. You'd certainly lose almost all content and most threads altogether. I can see an argument for a sub-forum but not applied to the whole forum.
However, the Rihanna picture (used purely as the first example I could see) is at least provocative, far moreso in fatc than many promo/magazine shots we get. The Julianne Moore post (again at the time puely an example and the latest I could find then) is just another talk show but to cap it off she's dressed like a Catholic Novitiate. From that POV both decisions are baffling and contradictory in extremis.
Generally, because I'm pretty new at the whole thing and using examples around of Mod discretion, I take the tack that as long as it doesn't break rules of being on a banned host or using an ad link or whatever and the subject isn't covered head to foot in an opaque sack [though you'd probably find someone on here who'd be into that (see the Julianne Moore talk show apearance)) then it clearly flies someone's kite so OK. I take that tack because a) it seems safest because b) there is no consistency to use as an example and the theory of "is it sexy?" is easily one of the most subjective questions on the planet. If you ask 50 people you'll get 50 different answers and I cant answer that for you any more than you can for me. That's why Mod discretion is so erratic.
Seen from that perspective you can understand why some people get annoyed, especially if they have spent a lot of time scanning and processing material and uploading it.
Cheers
BOC