Bounty hunters are by rule guys who are desperate to carry a gun and try to impose their will on people. They tried to be cops and failed, they tried to by air marshals and failed, they tried to be private security and failed. Any job that does mental screening to weed out the real wingnuts before issuing weapons is out of their reach. After washing out of every selective position they migrate into bounty hunting because cops have rules they have to follow and bounty hunters get to ignore almost all of them, so they wind up worse than the guys they're chasing. Three fewer dangerous psychos on the street and no innocent bystanders hurt, that's a good result.