I think the advent of social media and the platform it gives to crazy people is emboldening guys like the Christchurch shooter, James Holmes, Anthony Comello and Zach Madsen - Madsen is the guy who attacked a professional wrestler at a Hall of Fame ceremony a week ago.
Even on a smaller scale, we are hearing more about people doing stuff like pushing people off bridges for "social media likes" (one died because of this recently).
It's only going to get worse in the future.