When I was a teenager struggling to figure out the opposite sex my Dad offered me this advice: take an even strain. A nautical phrase (odd for an Air Force vet eh?). Good advice, and yeah, things didn't work out with that particular young lady. I hold her no ill will - I realized pretty quickly we weren't meant to be together. So be it.
Kids these days are not taught real or useful coping mechanisms. They're told they are all winners. They are given safe spaces. No-one is left behind or held back. They never really learn to deal with rejection, disappointment, losing. Thus when they are confronted with it in a situation beyond their control - they have no experience dealing with it. It is certainly good to win, but it is also useful, even necessary to lose once in a while.
A related factor in these rage driven school killings, is the deliberate attacks on honorable aspirational sex roles. The egalitarian fanatics have taken the ideas of honor & natural aspirations out of the adolescent goal perception--a very dangerous corruption of very basic drives, which were once respected motivations for honorable behavior.
Suicidal Rage vs. "Something Of Value"