I kind of call into question the idea that it will take more resources to create female models than men. Yes, in a game where they have both male and female models, they have to do all the work twice... But you don't have to put in more work just because they are female... I could see that if it was some non-human race or something...
As far as why Brink is getting all the hate for this. Well first, it's new. Second, they made a big noise about their character customization, then later on informed everyone that they are not going to have a basic and largely expected option in their game: gender. Third, other FPS games like Call of Duty or Halo are not real big on customizing. Some don't even offer any at all, everyone plays the same character essentially, only color swapped for multiplayer. Team Fortress 2 has no female characters, yet that doesn't get near the hatred Brink is getting over it. Why? Because there is very little customization in TF2. Every Red Heavy looks pretty much the same...
As far as 'it's a game designed for the male player in mind'. Well one, that's blatantly sexist. Some women like shooting people in their virtual faces too. The same as some men don't. Sure the majority of the players of Brink are likely to be on the male side, but not all of them. And secondly, since when do men not like looking at women, even in video games? The last I checked, the majority of the male population liked women...
Certainly it was the developers call to focus on one set of models for greater customization. That's their choice and they stuck with it, so props to them on that. However, given the outcry over the gender issue here, I and probably they should be questioning whether that was the right choice or not. In the end, This won't stop me from picking up Brink. I'm a bit irked by the lack of female options, but that's never stopped me from playing other games before either. The important part is whether or not the game is good.