The cops are the system. The people deciding in the moment what to do are cops, the people deciding who is going to be in those positions are cops, the people deciding the consequences for the decisions are cops, the people investigating abuses are cops. The people in oversight positions for the entire process are cops. The civilian government might be able to dismiss the top ranking leadership, the DA's office can choose to prosecute especially egregious behavior, but they have very little if any direct influence on the incentive structures for rank and file cops. Institutions like police unions typically have more control of the civilian government than the civilian government has on the police. This is a system that the cops both individually and collectively choose to participate in, and those who would seek to see it changed from the inside are forced out. Of course you can't place the blame on any one individual, and probably every person involved would like to see some change or another, but there is no shadowy cabal who designed the police to be what they are, they have done it themselves.