I think you're missing a very critical element: All Cops
Each cop, as an individual, is part of the police force as an institution. The reason the institution remains is people keep joining it and becoming the very thing that perpetuates the existence of the institution.
People who joined the police force after everything thats been happening after George Floyd are decidedly class traitors.
Doesn't matter how noble your intentions are. If you join the SS in hopes that you'll change it from the within, it doesn't mean you were one of the good ones. It just means you didnt really want to oppose the Nazis, just turn them to your will