but through societal decay brought on by a number of factors.
Learn ye' some history!
Do recall that in the early 1900s, we had locals setting off bombs that killed dozens if not hundreds of people every couple years. 1915 saw a spate of mass-shootings, set off by Monroe Phillips who killed 7 and wounded 32 more with a shotgun. Before automatic weapons, fire seemed to be the preferred tool, along with a good set of blades - Mass murders were pretty common in the 1800s, and that tended to be how they were done.
What's interesting is that this sort of things, at least the tools used and how many people die, seem to come in waves. Turns out crazy folks desperately want to be 'normal', in large part. But how can they be normal and crazy at the same time? Why, by expressing the crazy the way other crazy people do!
People who get in a situation like this do so because
they don't know what else to do. When people go crazy, they tend to go crazy in whatever way they can achieve that seems the most culturally
normal. This is why copycat events are such a big thing - people looking for an outlet to express the crazy get something to hook onto when they see it on the news and hear everyone talking about it, and begin seeing this as the "appropriate" way to deal with the issue. After all, it's what everyone else is doing! This is why places like India have a psychological conditions like "running amok", which doesn't really exist anywhere else - because people draw the "correct" way to express their problems from their surroundings.
If you really want to change this behaviour, what you need is to program some cultural preferred alternatives. Not an easy task though - people fucking LOVE mass murderers. They love watching them, and hearing about them, and talking about them, and there's lots of money to be made making them cultural icons. But this isn't new! It's been that way for a long, long time.