Perhaps you're new here or haven't frequented the forums but this is one of two or three periodic SOED's (Subjects Of Endless Debate). The simple answer is people post what they like. Whether they think it's art is up to them. Obviously, your perception my be different. Ironically, one of the other SOEDs revolves around whether anything created with Poser is really "art" at all or just hi-tech paper dolls. There are plenty of folks out there who would be happy to explain to you how nothing created on a computer is art as well. Within the Poser community, there are some who believe that if you use stock figures, textures etc. rather than making your own, that ain't art. If you want to start a debate about what nudity is "artistic" vs what isn't have fun but hopefully you're not naieve enough to expect consensus. Just render what you want to render, look at what you want to look at and accept the fact that everyone is different. It makes life a lot less stressful :-)

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken