Thing about games is that players don't want to play as themselves (the average person). Players want to lose themselves in the story and get the feeling that they are awesome. So in the case of male players, they want to feel like powerful bad asses. So as they progress through the game their character gets bigger and bulkier and in general more bad ass (or if there is not advancement system they start off as relatively big and bad ass). This is from society's perspective that men SHOULD be big, strong, intelligent, handsome creatures with a variety of charming personalities (suave, protective, brave, you get the idea), and gives us our own personal image of the ideal man (what we wish we could become). Which subconsciously makes men want to play a game as someone of these qualities (the reasons for men playing as women vary though). So the fact that women don't see how men are portrayed in games is sexist, means they are obviously oblivious to the fact that they are holding the same ridiculous standard for men that men hold them to.
Female players are no different than male players in the sense that they don't want to play as themselves. The difference is, that women inherently want to feel beautiful. You females may deny it, but you all secretly want approval from the opposite gender (or in the case of lesbians the same gender). Society has given you too the idea of what the ideal woman is, which you subconsciously will model your character after. So while this could possibly be considered sexist, that's rather impossible since it's the same deal with men.
Now then, statistically men play a lot more video games than women (A LOT more). Since sex is a selling point, and the main audience is male, daintily clad females will sell more games. Meanwhile if it is taken out or daintily clad males are added; it will make women feel better and maybe add a few more sales, but in the end will either drive away male players or fail to attract the male players to the game. Since men make up a vast majority of the sales, that means that your losing a lot of sales.
BTW most men, although they like to look at these definitions of a barbie doll, would never want to be in a relationship with one of these women. (I said most because its not true of all and I realize that)
if you couldn't figure out, I am male...