My guestbook is indeed the place where I invite people to comment on the web site. I even switched guestbooks specifically to allow larger posts, so you did right.
If the phrase "this hypothetical culture's interpretation is as valid as ours" confused you, then there's no arguing that it was ambiguous.
As far as male rape of females being a human, not a cultural, trait, I'll go one further. It's a mammalian trait. It crosses boundaries between species. Male bats, for example, sometimes rape females. A human culture where female rape of males predominates might be different enough that it wouldn't really be a human culture. (The culture would have to be populated by a species with a very different evolutionary history from that of humans.)
Still, one could imagine a culture in which fictional depictions of rape are seen as misandrist rather than misogynist.
Imagine, in the US, the fictional depiction of a black man attacking a white man. It would be easy to see that as racist (anti-black). Then couldn't a man attacking a woman be similarly misandrist?
Some depictions of male-on-female violence are, if not misandrist, at least unflattering to men. The Lifetime channel, for example, shows an endless series of "good woman, bad man" movies made for women.
Perhaps the issue is indentification. With whom does the player, reader, or viewer identify? (Richard Garfield brought this up in his comment with the example of scenarios involving dogs.)
In the case of the She-Demon, the reader or player identifies with the victim (as the She-Demon is a monster that, if it comes on stage at all, is likely to attack a player-character).
In the case of my adventure manuscript that left the game designer wondering why the PCs were always beating up chicks, the designer properly identified with the PCs (who were most likely male).
In the case of the black-on-white crime, most folks in the US (being white and moreover not being violent criminals) would identify with the victim. (Imagine such a scene invented by and for members of a black racist group, such as the Nation of Islam, and you could see the same scene as anti-white.)
In the case of the Lifetime "good woman, bad man" movie, the viewer identifies with the woman.
While one can't easily imagine (or even find plausible) a human culture in which female rape of males predominates, one could perhaps imagine a society in which violence is so discredited that folks there reflexively identify with victims in scenes of violence (sexual or otherwise). These people would see the She-Demon as misogynist, and they'd see a depiction of a man raping a woman as misandrist.
Obviously, the US does not have a culture were violence is discredited.