Playing violent video games is not a cause of real world violence.
Exclusively playing violent M-rated games and for 15 hours or more a week is a risk marker - associated with statistically significant risk of getting in trouble. This is true for both boys and girls.
But for boys, not playing any video games at all is also a risk marker. The researchers suppose that playing video games is a sign of social competence for boys and not playing at all is a sign that something is wrong.
A whole lot of people play games (63% of US). Yet we're still doing well and we'd see that if we stop paying attention to a causal link that does not exist.
Violent media does not cause crime. But if a person is at risk of violent behavior, an underlying factor may also cause them to consume violent media excessively. Or if they are socially isolated they may get into more trouble, and video games are a big part of how boys socialize now.
Seems like mainstream media has got cause and effect backwards. If the world survived Jazz and Rock & Roll, I'm sure it will survive video games.