The police have always served and protected the (white) wealthy land and business owners. It's why they were created. As that came to include (white) upper middle class as well. So of course all those people believed in the "protect and serve" motto of the police. Brcaue it was true for them.
But poor people and people of color were never intended to be served or protected. They were to be 'overseen'. Kept in line. And most of all, kept from disrupting the course of the status quo. And some of them approve of this. As there will slways be those who agree with their masters as a way of pretending they aren't enslaved.
Well, our whole society was based on the idea of Manifest Destiny. The police are/were a reflection of that, although the rise of organized crime indicates the point where the police were irrevocably compromised. For example, J. Edgar Hoover always claimed that "there is no mafia" and repeatedly denied the existence of organized crime, while his main focus was on political dissent, targeting liberals and progressives, as well as any group trying to elevate the status of people of color. In his view, Martin Luther King was more dangerous than the Mob and the KKK combined.
This view is still largely maintained in America, although it's presented in seemingly innocuous, politically correct terms.
The only real solution that I can see is to challenge the government and weaken the hold of the mentality in question. Anything that weakens the faith and confidence people have in government should be encouraged. A government's power directly correlates with the level of faith supplied by the body politic.