IMO these sorts of questions are kneejerk reactions without any significant fore- or after-thought. They only serve to disrupt the conversation.
In so many of these police related threads on HN lately people make absurd claims and then are upset when asked about data or objectivity, which suggests people are looking to complain about something and don’t want their complaint validated with data, which is strange.
In an ideal world where we have an oracle telling us which cops are good and which are bad your comment makes sense. But the nature of corruption is to obfuscate its dealings. You can't just say "well we need independent oversight" then because there are so many institutional pivot points where cops can hide their abhorrent behavior before it gets to see the light of day.