Far more people own guns now, so access to automatic weapons is easier and studies show that mass shootings spread in the same pattern as infectious diseases, similar to teen suicides. I imagine this has something to do with how human brains and behaviors are structured. We are social animals and built to respond to behaviors of those around us. Now a days that is spread by social media and the news. I also agree that bullying behaviors in schools are inadequately managed. Teachers, especially on playgrounds, bathrooms and halls are tolerated leading to students having to be violent to protect themselves.