Policing doesn’t cause crime and any more than umbrellas cause rain. Systemic issues exist but those issues are more about circumstances that produce criminals (breakdown of family structures, etc.) not policing.
Yes absolutely—people buy umbrellas because of rain, and voters employ police because of crime. It’s a logical error to infer that the presence of umbrellas causes rain, or that the presence of police causes crime.
In this metaphor, rain that doesn't happen to land on an umbrella just isn't observed. The presence of police increases crime statistics, because some marginally illegal activity that happens all the time and is mostly unenforced would be acted on.