I'd go a step further and say the yuckyness is in some cases purely subjective. You probably know about the guy who got into hot water over his manga collection. This is a clear example of a culture clash. For an american, or european, everything involving drawings of children in sexual contexts is at least distasteful. Strange as it may seem, there are cultures where "sexy" is closer to cute then to porn.

It's probably one of those things which 60 years after will sound _really_ weird, like blacks had separated restrooms or homosexuals liked to rape little boys.