It's actually pretty amazing the things people will hand wave when they think they have something to defend.
Honestly what makes videogames so fucking special that we get offended everytime the same level of critical and social examination every other media is subjected to is applied to videogames? A lot of things in our lives cause aggression, it's one of our most basic protective mechanisms, it activates when we're faced with challenges and when we're excited, it's a ubiquitous reaction to all sorts of things. And yeah, when I have a few bad rounds in the Dark Souls 2 arena I get salty and annoyed, fight a buffed longsword Havel monster a few times a you'll be pissed. And that's aggression, that's aggression that every gamer has felt and if you tell me you haven't you're a goddamn liar and know it. And there's nothing special about videogames, they just cause the same reaction as anything competitive, or driving in heavy traffic, or watching sports. Should we do anything about it? No, of course not, and no one (with any power or influence) is saying we should. But here's the thing, if you're aware of something's effect on you, you can work to curtail it, by acknowledging that this is a thing, you can consciously minimize it. And that's why gamers' knee jerk reaction to this kinda thing is so annoying, it just makes gamers seem that much more unreasonable and aggressive.
Seriously, these studies are done in the spirit of scientific inquiry because we like to know how our brains work, and people are acting like the very existence of these studies is evidence of an sjw conspiracy to take our games away.