People could just vote instead, which would be a lot easier. We get out of control mafia style police departments because the average local election participant is a 55 year old well to do white person, whose main concern (basically only concern) is property tax. Voter turnout for city elections (which controls the police force) is about 30% on average. You can't walk around protesting your government when literally no one even voted. Don't even get me started on primary turnout, which is like 20%. The system is not rigged, it is representing the voters, who are again, 55 year old well to do white people. They don't necessarily support police brutality, they just don't care, because it doesn't effect them.