As much as I want to blame this or that thing in society for the Texas shootings, in all honesty, the gunman was likely just a ball of mental problems and child abuse.
People want to blame guns or video games, but it's got to be more or less an issue of the guy not getting psychological treatment, and having parents that do terrible things to him, and teach him to solve every problem with physical or verbal abuse.
If someone at the school did similar things to him, he'd project his parents onto them. And if he felt he couldn't win against them, he'd grab whatever is handy to put himself into the abusive parent role.
What they don't think about is how they have become just like their enemy, and how they will face police and swat teams and things that will be unsympathetic, and they might just face abuse in a different form from them, or from people in the prison they may end up occupying.
And that's probably why they end up killing themselves or trying to die in a gunfight. If they could think that far ahead, they wouldn't have started shooting.