Yet police have one of the safer jobs in the USA. Loggers, fisherman, roofers, truckers, farmers, and construction workers all hold more dangerous jobs than police. A police officer is more likely to die in an accident (car or otherwise) than by violence.
And despite this, it's continually hammered home into their heads that they have a very, very dangerous job. Yeah, you're correct, it's fear from the lies told to them.