Sweet Jiminy Christmas, I hate women who do this. I run a tabletop gamer club at my University, and trust me, I get a TON of these women showing up thinking they're the greatest thing since sliced bread. It's not just video games though, it extends into other media. I think tabletop gamer girls are the worse because they think it's "so underground". A 4th-year told me at our last open house if any of us had heard of a game called WarHammer 40,000, a game she "discovered" only recently online.
Mind you, I haven't read what else has been posted here save for the OP (TL;DR, I know), but I think the problem lies in the general representation of gamers, be they tabletop or video. Video gamers are seen today as they were back in the 1980s, little kids with too much sugar and no parental supervision; whereas tabletop gamers are seen ass, well, Sheldon from Big Bang Theory. It's all so "cute", "underground", or just "different" for a lot of social media addicted kids of today (wow, I sound old) that they use their dabbling in it to form a contrarian image of themselves to set themselves apart from all the faceless "friends" they have online. It's like an achievement for some people to willingly brand themselves a "gamer", whatever their definition is.
All in all, I think being a "gamer" today is the equivalent of being an "anime nerd" back in the 90s was: a way to be just quirky enough to be different and thus be an individual (no disrespect to any anime viewers here).
EDIT: Actually, thinking about this, there are a lot of guys that I know who've done this, but not as many as women. Maybe it also has to do with the more weight women put on in-person social standing than men tend to.