Video games don't make people violent, assuming those people are old enough to be playing them. In nearly all cases where a kid commits a murder and someone tries to blame video games, the guilty party was too young to be playing the game in question.
When you're young, everything leaves an impression on you. When you're over 18, people generally assume you're smart enough to know what's right and wrong in the world, less you be retarded or something. So yes, video games CAN cause violence if you're playing GTA and you're 8 years old or retarded, but otherwise it's just as dangerous as music and film.
D12's 'Bizarre' raps about the most disgusting shit in his music, it's usually random crap about raping grannies and cumming in someone's eye etc. Hearing Bizarre say all that crap and not get noticed is just as likely to leave an impression on someone who may think "Oh wow, nobody seems to be in an uproar about Bizarre's music, maybe jizzing in someone's eye is okay after all!" But no, you kill one hoe in GTA and you're officially a violent gamer who will probably shoot up your school some day.