There's more to this than just wanton violence.

Teens arrested for plotting deadly school attack - Crime & Punishment - MSNBC.com

The key to why these teens were plotting this attack can probably be found in this one quote:

The boys told investigators that they planned to kill Quartz Hill students who had made fun of them, using guns and homemade explosives, then commit suicide, Brown said.

I remember when I was a kid (much younger than 15), teasing and bullying were quite common; and it was also quite common for teachers to turn a blind eye. I expect that's the same thing that happened here. To point solely at these kids and say, "they're the bad guys," is foolishness. I point MY finger at the teachers, the principal, and the kids' parents. What if these people had bothered to intervene?

Instead, now these kids, SUPPOSEDLY "our future," are full of hatred and self-loathing.

Good job, Mr. US Education System.

I think that if the justice department(s) started charging teachers and parents for neglect, etc, in conjunction with charging violent teens, you can bet your ass you'll see teachers and parents get off their lazy asses and DO THEIR FUCKING JOBS!!!