MK13 wrote...
... I respect other people's fetishes. Everyone should do the same.
Agreed, but it ain't gonna happen. Morality and sex go hand in hand and people get really touchy about things that they don't like. Also we must consider the stereotype for the sort of person who ends up commenting on Japanese cartoon porn on the Internet in the first place. Plus discussions of hentai generally take place on the Internet behind a screen of anonymity that allows people to be far more disinhibited in what they say and avoid repercussions. If they think you are jacking off to something gross, why not talk shit about you? What are you gonna do about it? They can fight an idea that they think is wrong with little to no personal risk on their part!
Discussions of fetishes and such in real life tend to be more civil. Or at least mine usually have been so. While I don't recommend asking random strangers what their favorite kind of porn is it can be an interesting discussion topic with friends that are not unduly ashamed of their sexual interests. I even had some hentai loving friends in college. My roommate and I would recommend each-other hot trap manga and my girlfriend and I would swap yuri stuff occasionally.