Psychos are usually clever and canny...not stupid...and they get ideas for destruction...ban TV? While this generation is pretty much screwed... what can we do for the future?
How do we prevent something we don't understand? First we need to ascertain their motives. Labeling them "psychos" probably doesn't help (though everyone does it).
A large part of the problem is Muslim Extremism, then you have bullying which torments people into action. Mental illness is another. There is no fix, we can only stand and fight against the bad guys in hopes of lessening the problem.
We have to change society, which is why this keeps happening. People don't wanna break out of their routines, their echo chambers, and their comfort zones. The ones in power wanna keep it,of course. These dynamics and separations of humanity cause alienation, fear, hatred, etc. So these class structures, the way we perceive each other needs to change.
We used to have places to keep crazy people from hurting themselves and others.
Granted, some of these places have horrible reputations. They are the ones that paranormal investigation TV shows frequent. But, crazy people can not be left to their own devices.