Don't be silly. Everybody knows that men are the disposable gender, and to add insult to injury feminists claim that men are sent to die in wars because they love it so much. So of course we're primarily going to slaughter faceless men.
In all seriousness, the disposable male stereotype is harmful. I don't like the term misandry because, like its distaff counterpart it has become a rallying cry for the ignorant, but there are legitimate examples of it, the disposable male being the most ubiquitous.
I don't think it is a result of malice on Bioware's part, though. Because the re-use of models, each enemy type will be designed with one gender in mind, so they can by copied and pasted ad infinitum. A good example of this is Cerberus in Mass Effect 3; Guardians, Centurions, Engineers and Shocktroopers are all male (despite the fact that a female model for these enemies could be created to add some variety), and the (more scarce) non cannon-fodder enemies like Nemeses and Phantoms are all female.
I suspect gender is seen as a design choice when deciding on the models for the enemies, making them all recognizable (such as creating recognizable factions such as the Venatori and Red Templars), or, dare I say, more cosplay-friendly. They have kind of shot themselves in the foot though, however in a way that most people (that have "valid and worthwhile opinions") will overlook. I wouldn't expect anything to change.
Maybe when they finish off that to-do list that Tumblr gave them they will start looking into this issue. 