Only true psychopaths kill for no reason. If your concerned about the increased mass shootings, as we all are, then we should really focus on the reason these shootings occurred. The guns are only a tool used to carry out a desire, in the mass shootings it was the desire to cause harm and kill others. In most of the cases the shooters could be diagnosed as sociopath but not psychopath. Alienation and disconnect are eating away at the fabric of society and have been at an increasing rate as we became a consumer culture, force fed false desires, in order to keep an insatiable economy alive and gorging. The entire system is designed for wealth accumulation and occasionally throwing the dog a bone. Is it really a wonder why some are filled with despair to the point of disconnect? These technologies when used for good will allow better distribution of wealth and encourage cooperatives. Unifying and potential to fulfill purpose will give back control to communities and allow for an actual democratic system to be realized. 
Can some psychopaths print some guns and case some harm? Sure they can, but the benefit to liberate and elevate the entire world population is not without risks. Nothing good in life ever is