My guess is that the OCC staff are just being cautious and for the right reasons.
We don't want a lawsuit brought against the site by Michelle Trachtenberg for posting fake nude pics of her. This isn't being dramatic - one of the other porn sites posted a fake nude pic of the French actress Sophie Marceau (Braveheart, The World Is Not Enough) a while ago and it led to all kinds of trouble. The site was nearly closed down because of a lawsuit which I believe was eventually settled.
Don't let it worry you or deter you from posting in the future - but just be careful what pics you upload to the site.
Best wishes