The answer is always, 'fear.' Because this socio-economic group are educated as to 'what is going on in the world.' as interpreted by what they get from the Media, they interpret the world as a hostile place. So many of us continue to fall for 'this big Con Job.'
According to the press, television, magazines editors (who do it mainly to sell copy) there are dangers everywhere, child predators, muggers, drug pushers, and the like. The fact that in a city of, say, 8 million people, 799,999,900 people didn't come to any deliberate man-made maliciousness overnight isn't newsworthy, you see. The News people will concentrate on the 100 who did have something 'bad' happen in their lives.
We live in a world where drama rules the airwaves and the printed news sheet. Good news stories don't sell, they are too commonplace and therefore mundane.