The 'cop in your head' is internalized social morals and ethics from the environment around you. It can include racism, sexism, discrimination against sex workers or people that do drugs, the homeless, whatever. It's that little voice in you head that says, when you see someone doing something that hurts nobody but is against the rules of the society that you live in, 'you should report them'. Or when you see an authority (like cops) do something that you'd normally be against (like fuckin murder), justifying it, because they're further up in the hierarchy, or the victim was someone that did something against the rules at any point in their life, or the victim is below you in social standing.

The cop in your head says it's okay when the sex worker gets abused or assaulted. The cop in your head says the black man that gets shot in the back must have done something to deserve it. The cop in your head says the homeless folks deserve it because they just don't want to work. The cop in your head says she deserved it when a woman is raped while wearing any outfit that makes her look like something aside from a formless lump. The cop in your head says the that it's rioters and looters when the people start taking back what was stolen from their community. The cop in your head says the protest wasn't legitimate because it didn't follow the rules.

So you can't just work on opposing cops in the meat. Otherwise, anything you build, any community you work in, can inherit those biases you mighty not even realize you have. Your kids can grow up treating people with different skin colour as lesser. Your organizations might not work as hard when it's helping people from a different area. You might end up building hierarchies that always seem to have men at the top, or that treat trans folks just a little bit differently.

ACAB. Find the cop in your head. Put a bullet in 'em.