>>17181116>Because you're training your dick to only get hard for women who are not and cannot ever be real.Firstly: live action porn is more-often-than-not photoshopped or otherwise edited. If we were going by your logic then watching porn is training your dick to only get hard to women with your preferred characteristics, thus if you like blondes, you wouldn't want to have sex with brunettes or redheads, right?
Secondly: I believe you do know that other than faces, hentai bodies are trying to be somewhat realistic. Yes, the breasts are very large and despite that are firm for example, but hentai artists are using your built-in instincts to create the perfect female body which is almost impossible to achieve.