I get your point and I think we agree on fundamentals.
I'd be careful about using US as a point of reference though, as their police seem to have very deep systemic problems. Not to say that other countries didn't have those too, but the US really is in a league of their own.
Shit sandwich is a good allegory and of course there should be fair and open investigation every time an officer is accused of misconduct. And in the end I find it more important that the police is held accountable rather than being let off the hook.