Where you find F-ed up stuff in the world, a bunch of horny guys who haven't been laid in years are usually not too far behind.
All this crap stemming from the Middle East is part of it. Cover you women head to toe and make sex hard to get and suddenly guys are going psycho.
I've heard about 10,000 US vets who were fighting in Iraq comment on how seemingly every last guy in that country was a 24 hour/day porn hound. Every time they would go into a house dude would be on the computer looking at porn.
Regular, positive, sexual interaction breeds contention and passivity, not a desire to drive a truck through a crowd of people.