We often talk of Eros the Greek god of love and sex. But we don't often talk of Thanatos the personification of death.
Human Beings acting horrifically makes me fall back on my studies of Psychology. I think of Sigmund Freud:
"According to Sigmund Freud, humans have a life instinct—which he named "Eros"—and a death drive, which is commonly called (though not by Freud himself) "Thanatos". This postulated death drive allegedly compels humans to engage in risky and self-destructive acts that could lead to their own death. Behaviors such as thrill seeking and aggression are viewed as actions which stem from this Thanatos instinct."It is not surprising that the suspected shooter in the latest atrocity had suicidal thoughts, and nihilistic tendencies. Being attracted to Assault Weapons, by and of itself, seems sort of sick. A sickness in the psyche. There is no reason to horde such weapons, except as some performative desire to wreak great havoc and death on themselves, and other Human Beings.
It is easy to find "defective" human psyches in our world. Seems the world can easily "hack" a psyche. And sometimes it's even an organized activity, for instance, see the US Marines, and Stanley Kubrick's "Full Metal Jacket." How to make a clean-cut kid into an efficient killing machine? Seems it is not that hard.
So yeah, what to do? You can't ban troubled Human Beings, but you can easily ban & confiscate Assault Weapons. All it takes is a bit of common sense and political will. Love & Death.