It seems the job selects for those types. I suppose people interested in law enforcement / justice that aren't that way either end up as lawyers or working for the FBI or something.
Or if you don't have any marketable skills yet have a spouse that has a job with health benefits, you can become a real estate agent.
Those two career paths seem to be the most chosen for almost all of the 'not so bright' folks I grew up with.
Power corrupts, or some half baked version of that.