The problem is, many "art" forums like that re for people to showcase 3d content tthey've developed themselves. In other words, they've started from scratch, and the image you see is the whole package.

There are many such forums for this type of showcases, and posting poser renders to them is kind of like showcasing a colorforms picture in an art gallery.

They are expecting to see a completly original creations, and people posting with other people's content or creations isn't "pure".

Stonemason posts in forums like that, but gets away with it because he is actually creating the content himself.

Way too many people take way too many things way too seriously.