Does feeding Christians to lions and public executions make a more peaceful society?
Being human makes you violent, higher reasoning negates it. The problem is when that higher reasoning no longer functions, either though mental illness or other impairment, and society doesn't have the ability or the will to recognise this and provide adequate support to individuals in order to prevent violence from occurring in the first place.
My parents taught me right from wrong, reality from fantasy, and I understood; if I had at any stage displayed signs of difficulty in grasping these concepts then my tribe (family, friends, teachers etc) would have intervened.
In reality, we're probably not exposed to more violence than we have in the past, we just no longer feel a responsibility to our fellow tribe members. Take the Jimmy Savile case for example, supposedly everyone knew he was a paedophile, yet no one said anything; reporters even knew and yet they didn't expose him, why?
More mental health support and less pious judgement.