GAF being hyper internet aware, a video game forum, and incredibly liberal (by comparison to the rest of the country) is naturally going to talk a lot about gamergate. The rest of the country doesn't really even know about it; much less the blue collar voters that made the difference in this election.
No one is saying that mainstream America knows or cares about gamergate.
Gamergate was an event that coalesced and galvinaized internet trolling, which fed into into broader support for alt-right media founded on anti-political correctness. Gamergate is how some people got into Milo, then got into Brietbart, and got into spamming the Internet with pro-Trump and anti-Hillary sentiment all over social media.
We all felt the atmosphere this election season, that the online world of Trump was this mania of vicious trolls ready to spam every poll or attack every dissident? Gamergate was a feeder school into that. One of the elements that fed into the wave.
A lot of this bubbled up to normal people in their FB feeds and in their real life discussion, whether they were aware of it or not. I saw Milo's videos getting posted on my Facebook feed, by people who'd never played a videogame in their life. And that's the most obvious link from Gamergate to Trump support. Maybe your grandmother came to view Trump as favourable, and she'd never touched gaming or social media. But she was unwittingly on the receiving end of info that was ultimately pushed to her friends via social media, pushed by trolls who got interested in trolling for Trump, via a Gamergate gateway drug.
Trump supporters needn't have jumped on with Gamergate, but it was one part of the wave that pushed a wild-eyed anti-PC Trump-obsessed online alt-media into people's faces.