It's called societal decay, has nothing to do with firearms.
Listen to Mr. Henderson Ong speaking at the gun violence prevention hearing.
https://www.youtube.com/watch?v=XUi6LOl49s4
Again we cannot deny the real facts about gun laws:
Most other advanced nations apparently think so, since they make it far harder for someone like the Charleston killer to get his hands on a Glock semiautomatic handgun or any other kind of firearm (universal background checks are common features of gun regulation in other developed countries).
Germany: To buy a gun, anyone under the age of 25 has to pass a psychiatric evaluation (presumably 21-year-old Dylann Roof would have failed).
Finland: Handgun license applicants are only allowed to purchase firearms if they can prove they are active members of regulated shooting clubs. Before they can get a gun, applicants must pass an aptitude test, submit to a police interview, and show they have a proper gun storage unit.
Italy: To secure a gun permit, one must establish a genuine reason to possess a firearm and pass a background check considering both criminal and mental health records (again, presumably Dylann Roof would have failed).
France: Firearms applicants must have no criminal record and pass a background check that considers the reason for the gun purchase and evaluates the criminal, mental, and health records of the applicant. (Dylann Roof would presumably have failed in this process).
United Kingdom and Japan: Handguns are illegal for private citizens.
While mass shootings as well as gun homicides and suicides are not unknown in these countries, the overall rates are substantially higher in the United States than in these competitor nations.
While NRA supporters frequently challenge me on these statistics saying that this is only because “American blacks are so violent,” it is important to note that white murder rates in the US are well over twice as high as the murder rates in any of these other countries.
http://theconversation.com/how-us-gun-control-compares-to-the-rest-of-the-world-43590
I know this article is from 2015, but the statistics for the USA have got even worse.
Australia hasn’t had a mass shooting since 1996