I thought I had seen businesses run by every conceivable group, founders, engineers, sales, marketing, finance... and then I saw a hospital and realized it was run by HR. Every "may" in a rule becomes "shall" since anything else could be perceived as preferential. It makes the lives of both supervisors and supervised hell. Only the spiteful or incompetent rise.

Of course the "why" is driven by the greatest risk in healthcare. Where most income comes from insurance is stable, the real risk is being sued. Hence rises "there shall be no exceptions" HR rule based hegemony.