"Hardcore" is perhaps the wrong word. But I was referring to the "Triple-A" titles, the ones with storylines and high production values, as opposed to "casual" games which require a lot less investment (monetary, temporal, and emotional). Wasn't referring to violence or fantasy setting or whatnot. I would categorize The Wind Waker as a hardcore game.
And while those games might have female fans, they're a vanishingly small percentage of players. That's where the mystery lies. I don't know a single woman who has played Assassin's Creed, but I know dozens who play Angry Birds. So the question is, how would you make a game like AssCreed more appealing to those lost 49 percent or so of the market? Having a female protagonist in there would do squat for sales, I believe. It would still be men buying it, playing it, and enjoying it. Look at Tomb Raider. I think it's all down to what culture says you can or can't do.
Angry Birds - ok.
Assassin's Creed - for kids and manboys.
I don't agree with it. Neither do these fangirls of which you speak. But we're not representative of society in general, and it's society in general which needs to change if women are going to start playing "Triple-A" games.