"Unfortunately, examples such as the kid who shot his parents, killing his mom, for vengeance"
That particular example, had more to do with parenting, addiction, and psychological problems with the child. The video game itself was not the cause there, IMO.
I kind of have to agree with the judges in this case. However, I hope this ruling will not prevent folks from preventing very young children from buying software/games which display adult content (nudity, porn, etc). That goes beyond free speech, and begins to intrude on another person's rights (which is why you can't run naked in public without being arrested).
I've played video games since I was 5 or 6 years old. I've played most of the GTA games, Halo, COD, and lots of FPS games. I've never had the inclination to hurt another person due to this.