Ooh, I have an awesome idea: let's use math to prove he's an idiot:
Baca's Theorem: Warning labels exist if and only if they warn of actual danger. (in English: if there is danger, warning labels exist, and warning labels exist if there is danger. If and only if statements have to be true forwards and backwards)
Definition: Danger-the supposed relationship between playing video games and violent, anti-social behavior.
Counterexample the first: Despite having played ME2 (gawd I love that game) and Minecraft excessively, I have only murdered three people today, and they really deserved it. Cut me off, bicyclist, will you?!!! Therefore, no danger exist. Therefore, Warning labels may exist without the actual danger being real.
Counterexample the second: I am able to buy both video games, alcohol, and firearms at Walmart without any warning to the danger that this combination may pose. Therefore, danger may exist without warning labels.
Via 2 counterexamples, it has been shown that Baca's Theorem is false under the provided definition. Consequently, Baca is an idiot.
Oh, what's that you say? There isn't actually an established link between virtual and real life murder? Aw, but this is creative math...