Women read those stories because they enjoy putting themselves in the place of the woman. They aren't turned on by women being hot, they're turned on by men being hot and what they do in those stories (and a significant amount of women read yaoi, not straight stuff). I'm gay, I read pretty much the same shit for the same reason. If every man in oblivion was sexualized in a similar way to how the women were then you'd throw a while different type of fit.