The idea that Anita introduced the discussion is at least "arguable" and definitely comes across as something thought up in retrospect. A more feminist or socially aware perspective was something being increasingly talked about since at least the beginning of the 00's (within the enthusiast press that is, you'd have to go back more than two decades for it to be truly novel - maybe slightly less so if you disregard the ol' "Christian Moms" angle, but not so much if we are talking about academia and studies or gaming magazine fan letters). This would just mean videogames are following the same trend as every type of media is.
I would say it was around 08 or 09 where it was basically a "thing" you commonly saw people fight over, often in the context of the Wii and mobile success among casual gamers (ie not young, possibly-white male bro-gamers or computer geeks, who may have been accused of elitism or gatekeeping). When I first saw her stuff, starting with the Bayonetta video, it didn't come across as something new, but rather more of the trend. It was already a bit of a battleground when it came up in game journalism, with no less defensiveness in favor of the games and developers. There had already been quite a few controversies (see: Jade Raymond, booth babes, or how several reviewers reacted to Dead or Alive Xtreme Beach Volleyball for an obvious example). Consider how NeoGAF was already hot on the idea of banning "sexist gamers" and certain mods became infamous for it. Also consider how most of Anita's material mainly comes from TVTropes, as in there was already a huge website saying what she was saying (it's not as if Gail Simone's famous "women in refrigerators" comment was only applied to comic books).
Google search "game sexism" with no results dating later than 2009 and you get plenty of stuff from (relatively) mainstream gaming sites and blogs (the material is endless if you consider minor blogs and forum threads):
https://www.destructoid.com/european-politicians-worried-about-sexism-in-games-102416.phtmlhttp://kotaku.com/5052721/on-gynophobia-and-misogyny-in-games-and-gaminghttp://jezebel.com/333238/gaming-industry-is-full-of-sexist-geeksOn the other hand, it's obviously a moment you can point to as a sort of boiling point, but I would think, especially if we are talking about mainstream attention beyond the enthusiast press (albeit short-lived or quickly consumed as a detail in more pressing matters, like the "alt-right"), GamerGate overshadows it greatly. The link between TvW and GameGater, to the point that they sort of blend in as one thing, kind of highlights the point that the actual ideas involved weren't as important as the harassment (the kind of which wasn't really new if you were following some BioWare drama) or the growing divide between game journalists and a significant segment of the audience (including the idea that the segment was the story more than anything else). So, in terms of game criticism (to which many of her fans will admit was pretty shallow), maybe as not important to the point where it is inarguable, but in terms of gaming being in a moral crisis... sure.
I kind of regret writing this much. Plz don't call me gamergate.