I'm sure a lot of people involved in just providing volume for harassment are younger but a lot of this as a thing seems driven by people who are out of school with not much to look forward to who feel like their one sphere is being invaded. I think if I were to stick an overly simple psych read on this situation I'd go with "status anxiety" over "adolescent sexual frustration" basically.
The ones that stand out from the egg accounts are mostly the ones who have some kind of youtube channel or online radio show. A lot of them are anonymous but through years of shit-slinging and stepping on toes with the likes of 4chan readers, their personal information is inevitably leaked and they conform to basically ever stereotype of the angry white neckbeard you would expect. White, late 20-something dudes from shit towns in Britain and the U.S., obsessed with video games, but living somewhere with no opportunities to get into the tech sector, either didn't go to school or went to a shitty one, etc.
The same is true of the guys who have latched onto the movement as "game devs," trying to lend some kind of industry-associated heft to the mob despite being aspirational outsiders who think their bland pixel-nostalgia game will make them the next phil fish. Since they're using real names to kickstart their projects, you can see all the same trends; white guy, shit town, no connections, freelances or works at the bottom of the bottom rung in tech. It's easy to see why these guys dig their claws into anyone who seems remotely ascendant in games or tech, and even more so someone who might have gotten exposure due to Undeserved Privilege of being not a late-20's angry white guy; this is their dream, and the bright interconnected future of the internet has not made it one iota more accessible for them. But it has made the people who do get the golden ticket much more vulnerable.