I'd argue that nobody should help the police as they exist in many modern implementations, because the police as they exist now are often bad actors. But it's not hard to imagine a police force that's held to a higher standard such that they actually are trustworthy. The argument doesn't have to be "police shouldn't exist"--it could be "police should be better".
My previous post was responding to your claim "But an argument that no-one should help the police is basically an argument the police shouldn't exist", which is incorrect. The two are very different arguments.
I take "not helping" to mean not just not developing specialized products that only police can legally use, but also not calling the police in case of crime, not helping them with investigations as witnesses. Where the law permits, not selling them generic products and services (eg food). And where personal circumstances permit, not working for a company that does business with them, deplatforming them, etc.