I think perhaps the difference is when women see a naked guy, they don't necessarily get turned on by it, they may find it nice to look at and appreciate it, but that is about it, whereas men, well most, probably get highly excited by the presence of the naked female body., that is most likely why men donot find it offensive to watch lesbians, as it is still the female body, and they probably derive some pleasure at watching them, but not so with the male to male, just MO.

There is nothing cutier than a nice male butt in a g-string, but yes not bad in jeans as well lol.