Do we need to submit identity proof to a porn site? That's ridiculous. If I was ready to my proof to mtgox 3 years back, I would have bought good sum of bitcoin for cheaper price. So, asking identity proof to a porn site, I will google some free sites and free stuff.
You don't need to submit an identity proof per se, but you will be needing to prove that you are more than 18 years old. So by default, an identification proof is required. The porn sites are helpless in this matter. If someone can prove that these sites could accept individuals less than 18 years old, then they will get blacklisted, and probably banned.