Interesting stuff as always. Though I would offer a counter-point to the first point made in the video. While I do feel it's stupid to try to out someone as "fake geek", I'm not so eager to apply a sexual motivation to their actions. There's a very good reason that geeks don't want beautiful people biting their style. A subculture made popular by the mainstream eventually is sterilized and watered down to be fit for the masses. A more paradoxical way to put it is that if something becomes special to everyone, it's ultimately special to no one.
As a parallel, I would point you to other subcultures. Look at punk rock. From its point of origin, punk has become excessively mainstream. It started small and early, with movies like Valley Girl, which depicts the "punk" music as fashionable new wave, in direct contrast to the awesome punk bands that were actually making a splash in LA at the time (Dead Kennedys, Black Flag, The Germs, etc.). It ends with the MTV punk bands from the late 90's and into the early 2000's with 25 year old, attractive men singing about girls like they're an overweight teenager (all while making much bank).
It happens all the time. Subculture is misinterpreted by the mainstream and/or by people the mainstream pays attention to. The mainstream reaches more people who are naive to the roots of a culture, thus relaying the misinterpretation. It creates this negative spiral that results in a separation of a subculture. Subcultures within subcultures, etc. You don't believe the thing you love can be co-opted by people you don't want to be associated with? Look at the skinhead culture that started in the late 60's. A non-political culture that encouraged unity through shared love of reggae music and roots in the working class. Yet, because of more media attention, racist skinheads that began to prop up later in the scene's history now are all anybody thinks about when they hear the term "skinhead".
However, I am in agreement that it's uncalled for. Cultural gatekeepers are something that every subculture has had. However, they NEVER stop assimilation from occurring. The best thing you can do is the reverse approach and engage people who don't know about the subject. You meet a woman who's dressed like one of your favorite characters, but doesn't know "the lore" like you do? Talk with her. Engage in conversation. It's more likely that you'll be able to drop some bits of knowledge. She may walk away more educated about the medium/character/lore and you don't look like an asshole. Everybody is better for it.