Traumatized people, particularly Developmentally Traumatized people with disordered and insecure attachment, feel like the whole world has rejected them. This is what shame is.
Not unreasonably, they ask “what about me?” as the world goes about its business, not realizing it was supposed to notice or care about them. That was certainly someone else’s job, and it just didn’t get done.
Such people will alternate between conformism–which can be so deeply reflexive that it appears to them natural and what they want–and an anger whose source they don’t really understand. It feels foreign, like something outside.
But school shooters are attacking “the world”. And the countless people who relentlessly watch violent media are committing acts of violence vicariously.
Niceness means nothing.
And listen deeply to people. Not infrequently you will hear calls for help from the bottom of the well. Feeling heard, even for a moment, even from a stranger, will help bring them closer to the surface.