Oh boy, here we go! I always see at least one of these types of threads a day on various sites. I think we can't discuss what constitutes a "girl gamer" without first addressing what the definition of a "gamer" is in general. What sort of criteria does a person have to meet in order to be considered a gamer? Do they have to play genre X for Y hours per week on platform Z? Believe it or not, that is the argument I most often see. But who are we (I use the word not to mean AltTabMe, but people who play video games in general) to determine who is or is not a gamer? Is the College Fraternity member that plays only CoD and Madden any less of a gamer than the semi-professional Starcraft 2 player? What about the 12 year old who really enjoys Pokemon and Super Mario? The point is, throwing around the label "gamer" is practically useless now. We need to stop viewing "gamers" as the stereotype of the grown man living in his mom's basement playing WoW. We not only exclude many people by doing this, we deny ourselves the opportunity to expand and diversify our love of games.
"Gamr gurls" might eat Xbox controllers primarily for attention, but if (even only deep down) they truly enjoy playing Call of Duty, I would consider them a gamer.