Another commonly-held notion that the idea of female-on-male rape challenges is the false idea that since men have erections, they enjoy the sex, and hence is not rape or not as traumatic as any other kind of rape. Therefore, the idea that the man could have either not consented to sex with a woman or been incapable of fighting off a female aggressor if he did refuse sex is simply not taken seriously. Men are stereotyped as constantly wanting sex and of being stronger in general than women.
But there seems to be one exception: when the victim is a man and the attacker is a woman.
Rape Is a Special Kind of Evil, beyond kicking the dog or any of the other acts of villainy in media.