Yeah, I think that was part of the point the article was making. The people were definitely around and active, I could point to a lot of them on 4chan and some similar websites, but gamergate was a shift where things changed in nature/direction. The shift with gamergte was that the sentiment of what we call alt-right and similar folk started to coalesce into larger and better organised groups and people already in other organisations (media, politics) saw what was going on and either organically or deliberately manipulated the situation in combination with new media for their political and social purposes.
I recall 15 years ago receiving those chain emails about climate change and politicians - this is before internet memes barely existed, we're talking in the time of flying toasters and dancing babies - that were completely fabricated and designed to manufacture outrage among the less informed and more biased. I used to try and point out some of the BS in these to mates that sent them but regularly just got pummelled with more contrived BS by people thinking it was actual evidence: "Then how come I got this other email the other day that says exactly the same thing?". No one was asking who wrote it and where they got their stats and info from, because it reinforced their biases and it's easier to get worked up about something and provide simle solutions than ask hard questions and admit that you're unable to be part of the solution, because you don't know how to be.
I think there has been a growing realisation by disparate groups that social media, modern psychometrics and some of the disatisfactions that exist in societies are useful in achieving agendas. I think the rise of viral marketing and things like the Kony 2012 experience have kicked a new era into gear and gameregate is one of possibly numerous inflection points were new trends are emerging and becoming identifiable.