Sony does not allow Hentai because Sony is teh k1dd13.
It's made by the company known for the Oneechanbara games (zombie slasher games with girls in bikinis as the heroes, one of them is coming out in the UK in february* and I'm so going to get that). They're also responsible for the game that comes up when you press next.
*=Guess what, this is ALSO coming out in February. EVERYTHING comes out in February. Man, I'm so going to be bankrupt that month...