There have been shooting just about everywhere. In USA much more frequently than any other land living in peace(*).
The choice has been made by majority of US citizens - we and our criminals want to have free access to guns. There is no way any shooting will change that. If it does then it only increase amount of guns sold. This assures that the business will continue with new better guns. this is a tragedy only because there is a sizable minority in US that disagrees with this.
* - by peace I mean a state of peace that most of Western countries enjoy on their soil whereas some of those countries' armed forces take part in various adventures around the globe (which may or not be a moral hazard but that is not a topic here).
"The pyramid is opening!" "Which one?" "The one with the ever-widening hole in it!" -- The Firesign Theatre