But because there is no visible Cold War, no Vietnam, and no conflict - and we've truncated ourselves from the inner cities and gang warfare, a false sense of security and immortality has been birthed. When death isn't real, then no one needs to be 'desensitized' to anything. There is no guilt or sorrow associated with loss of life because it's always 'just on TV', or never seen at all. So, when someone persecuted, depressed, or just seeking attention decides to 'deal with their problems', it stops being such a stretch to pull out a shot gun and blow away some people. Often, the killers reveal their plans to other students around them.
Nothing is done, because none of the other students see death as an actual threat either.
They prepare the attacks long in advance and give plenty of warning. But if those who hear the warning don't see death as a threat, it is often dismissed. I mean, I know several people who I went to High School with who had a spark for the darkly creative. Just a thought. A Look at Russia's current government, and their involvement in Kosovo.