Nothing good ever comes of violence.
There are two types of violence. One is perpetrated by “amateurs”, is usually impulsive, and can be due to mental health problems. The second one is perpetrated by “professionals”, is usually planned, and can be due to secondary gain issues (military, financial, political).
Treating and preventing mental health problems could significantly reduce societal violence. We have developed tools to help clinicians with the more precise assessment and treatment of mental health issues. Is it possible to screen for violence risk factors in a systematic way like we did for suicide risk? We are working on that.
In the meantime, reducing the cultural contagion from violent video games and media depictions would be a good start. That is area where common sense, decency and self-restraint do not seem to work, and thus there is a need for societal/governmental regulations.
Live. Happier. Longer.