So, why does Sarkeesian get singled out by gamers for doing what gamers do? I think it is because the gamers who attacked her felt threatened by her perspective.
She's a con artist.
She made a fortune from her Tropes vs. Women Kickstarter by publishing hate mail messages. Even though her target was $5,000, she received $158,000 from feminists who sympathised with her.
The quality of her videos before the Kickstarter were awful. Her videos are poorly researched, full of factual errors and piss-poor arguments. And even though she received more than thirty times her target for the Kickstarter, the Tropes vs. Women series were no improvement, despite taking years to produce them and having approximately $30,000 to spend on each video.
One of the things that really stank about her videos was that the work she did did not even require $5,000. Other Youtubers produce the same kinds of with better research. The stated reasonfor needing the money was to buy video games, but much of her content was taken from other Youtube videos, meaning that she didn't use the games that she needed money to buy.
Despite the poor quality of her work, she has become famous, giving talks at TEDx events and appearing on TV, not because she provides any insight, but because the hate she attracts makes her a heroic figure in the eyes of feminists. And the more undeserved success she gets, the more hate she attracts, and the more support she gets.
The end result is that a lot of people, really, truly hate her guts because she's a fraud who is making big money by attacking their pastime, and a lot of other people think she she is a hero for shining a light on the evils of video games while bravely standing up to rape and death threats from gamer bullies.