Blah, blah, blah.
I have one word -- just one word -- that renders your entire argument moot. You want to know what it is? Alright, here it comes:
EUROPE.
Somehow, the police in Europe manage to deal with the same kinds of crime we have here, yet manage to do it without killing nearly as many people as our police do. One statistic I've heard is that American police killed more people in March than the UK police have since 1900. That's one month vs. more than a century. (And I don't care that the US population is higher; it doesn't matter -- we're talking orders of magnitude here!) There is no explanation, other than American police having a SYSTEMIC problem of incompetence, corruption, and needless brutality.
Also note that, while bad cops are bad cops, "good" cops that cover for bad cops are bad cops too. The problem in Ferguson and Baltimore is not that one bad cop fucked up, it's that one bad cop fucked up and all the other bad cops -- namely, the vast majority of the cops in those jurisdictions -- defended him!
In other words, it's "only" 99% of cops who make the rest look bad.