Not all true
This wasn't a great movie. Even if the statistics show that anger is caused by video games, like most statistics, they are probably irrelivent. You have to take into consideration, maybe stress is causing the anger and they are just playing the "violent" video games as some kind of release. These people you tested aren't angry at all times, perhaps you caught some of them at a bad time? Thats why these statistics most likely right, or wrong.