I see nothing wrong with hentai. The fact is, hentai is actually alot safer then real pronography and it should be encouraged. People still get to have visual stimulation, without anyone getting a paycheck do to it, there being risks of stds, nor the embrassment of knowing your parents were porn stars..
So it's not only safer, but it's much easier to get straight to the point of ass-pounding or whatever it is you fancy in pornagraphy because they aren't people. So it's just raw stimoules.