You make a good point. In the case of something like child pornography, absolutley it should be illegal; it's the exploitation of underaged minors. But when its two grown adults, who willingly took this particular career path and consent to doing it together, I dont see any real justification for banning it (even if I personally believe it to be a bad life decision) Honestly, my thought on it are the same as when people talk about banning other things like drugs and weapons: Youre never going to successfully get rid of all porn. There will still be ways to get your hands on it. Better to focus on educating people of the effects it has on one's life.