A bit short, but it was easy enough to read. I like that you provided your sources...
As for the matter at hand, I think that video games (competitive) + anonymity = breeding grounds for bad behavior. I don't think that most people get online with the intentions to become a troll, but I think that being exposed to it will change you and your ideas about it. I have been online gaming since I was 9. I am 21 now, and have spent far too much time online. I have noticed the most toxic communities are in games where skill is a major factor. In non-pvp MMO's, there are relatively few toxic players. Go play a PvP game, say ArcheAge, and I would say half the players are "trolls."
But I guess we gotta talk about what a "troll" is.. Because there is a very large distinction between toxicity and trolling. Toxicity is just a bad attitude and often times unchecked aggression, most of the time these players are just acting out of frustration at events. Trolls, not so much. Trolls are an inclusive group. If you talk to a pre-teen gamer, being a troll is cool. Go on twitch chat, plenty of them there. Here's the deal: it provides a social group for people. I would say the majority of trolls are harmless and just doing it for the "lulz." They have their own sense of humor, while it can be antagonizing, it doesn't mean anything. Most trolls hold the same attitude in person as they do online, because they spend so much time online, the internet is ingrained into the psyche. Which, I feel, plays into the internet confidence from the article. The internet becomes a second home for anyone who spends enough time on it. It's just a playground.
I think you should define what a troll is. Because the trolls I know aren't malignant, they just don't take online interactions seriously. I think cyber-bullying unto itself is a different breed from the troll.