Why is it that the same people who think the solution to bad public schools is more oversight and accountability, seem to oppose increased oversight and accountability for bad police departments?

There's no indication that funding is an actual problem that a lot of these "bad" departments face. Teachers regularly have to buy their own supplies for their classrooms. Have you ever heard of a cop needing pay out of their own pocket for ammo for their service weapon, gas for their patrol car, or batteries for their radios?