> How a cop treats someone they view as a "scumbag" is a lot more illustrative and important than how they treat those they view as "upstanding people."

I absolutely agree, but the point was not that it doesn’t matter how cops treat “scumbags”, but that you can’t trust some people’s word on what they experienced. I think it is certain that there exist both cops who lie and non-cops who lie, so we need some way to filter out the signal from the noise.