It's a two part problem. We have a broken system that draws in fundamentally broken people, and does its best to break any who showed up okay. 90% of people who choose to join a police force in modern America should absolutely not be there. But those 10% of officers who genuinely do join from an honest desire to protect their community are being legitimately traumatized by their training. We need change from within the system but "the system" in question has a stranglehold on its members.