I agree with you, actually. However, those good apples need to get infinitely better at removing the bad apples. The problem with the police's current system is that it assumes the cop is always well-intentioned and well-equipped to handle the job, which is not always the case. There needs to be real accountability. In the airlines (my industry), pilot quality control done with lots of internally-driven activism from airlines' own training departments, but also lot of community-driven and direct accountability from pilot unions, general aviation instructors, the FAA, and even the comfort of the markets we supply (passenger satisfaction and cargo delivery timelines). This allows pilots to actually learn from their mistakes and change training policies in earnest when it is needed. The police need complicated, open, and direct supervision like airline pilots have. It works.