Sometimes things are simpler than you think.

Lousy parenting and shitty teachers turn sweet little kids into monsters.

You needn't have been well-parented yourself to learn how to be a good parent to your own kids. You just need to believe they are more important than anyone else or any thing in your life. It's basic instinct.

If people are incapable of doing that, then yes we must ask why. If people are actually brain-damaged by various pre- and postnatal exposures, we need to diagnose that and admit that and devise remedial strategies.

But in far too many instances people use their intelligence and other abilities for ill and not good.

First end the excuses so we can as a society weed out the vile from the genuinely physiologically damaged.