A friend of mine was shot and killed on Monday. The shooter was 17. Existing gun regulations don't affect him. Stricter gun regulations wouldn't affect him. Most of the gun violence in this country is perpetrated by people who are so far removed from "normal society" that institutional laws and regulations don't really have any practical effect. The U.S. is crawling with impoverished neighborhoods where law enforcement has very little power, and each one is already saturated with firearms. Even if, beginning today, another gun were never sold, we would still suffer from gun violence for dozens, perhaps hundreds of years.
I agree, we shouldn't try to do anything. 
Parents could maybe, oh I don't know... perhaps raise their children to be respectful and considerate of other people, that killing and robbing, etc, others is wrong, and/or not to be whiny sociopaths who feel they'll 'show the world' by going on a shooting spree because life was mean to them.