The reason pedofelia is looked down upon is VERY different from the reason that some cultures look down upon homosexuality or other sexual behaviors. The reason some people think that homosexuality is wrong is because of a book that has somewhere between little and no scientific basis on which to claim morality. The reason pedofelia is wrong is because the object of sexual attraction in pedofelia is a group of beings who are not capable of defending themselves from unwanted sexual advances, or in many cases are not even capable of recognizing exactly what a sexual advance is. The difference is clear, homosexuality has NO victim (unless you want to contend that it's practitioners have damned themselves to hell, I make no such claims myself), which is why it's only considered culturally wrong (and I for one don't consider it wrong at all), pedofilia clearly has a victim, which is why it is absolutely wrong.