I think the police's role in state sanctioned violence is a fair distinction, but is violence the only important factor? I have seen a lot of arguments against

I think the police's role in state sanctioned violence is a fair distinction, but is violence the only important factor? I have seen a lot of arguments against unions for e.g. harming children by protecting bad teachers; some would argue that the education of future generations underpins a large section of systematic inequality within our society, including poverty and crime, which are issues that also happen to intertwine with the problems surrounding police violence. Bad cops are easier to spot than bad teachers so I understand the impulse to dismantle systems that openly protect them, but I am not convinced that unions themselves are actually the issue.