I think there's a distinction here: Cops face far more stress on the job than garbagemen do. Which in turn can make their job more dangerous than need be because a stressed cop worn thin might escalate a situation that could've been handled better, or otherwise just make a wrong choice because of what they've dealt with.
It's a very stressful job that will inevitably have them seeing things that are hard to see, and unless they're devoid of empathy the constant march to the same battered women calling in abuse only to refuse help also takes a toll. And constantly dealing with dishonest, devious, violent people can make you jaded and bleak, which doesn't help the mindset.
There are jobs that are more dangerous and deadly than being a cop, but the stresses that go with being a cop can be rather unique. I've never seen this done before and it's a while since I've searched for it, but I wonder how many of the veterans who commit suicide are also on police forces. Piling more PTSD on top of existing PTSD to get a more well-rounded PTSD portfolio cannot be good.
