It's the self esteem crap being taught in the public schools. Everyone deserves a trophy, and everyone is equal. When that turns out not to be true, and a kids self esteem gets hurt in the real world, the kid sees it as an attack. They don't know how to deal with it, so they decide the only way to rid themselves of reality is to abort those they believe are the enemy.
Because we have a culture of death in this country, killing is not seen as something out of the ordinary. It's "justified." Simply abort the inconvenience, and the problem goes away.
Race hate, envy and sin - the hallmarks of liberalism’s power structure.