Fair is Foul and Foul is Fair

Every time I asked this boy (P6) solution to problem like the manila hostage, he would say "I'll kill that man." I said, "You know you won't." He said, "I can." "I know you can, but in reality you won't." I asked him if he didn't like to think about the problem or he played too much video game. He said no. "I'm sure there're other solutions that are better than this one. Why do you keep saying this?" He said "Because I am very angry." A little boy holding a lot of anger towards unfair incidents and he could only use emotion to lead his reaction. What on earth have the adults done to him? What on earth have we taught the young people that they can only use voilence to express anger?