A reader comments on the meme here: I think it comes from the notion that generally police are supposed to be the best of the best, the ones charged with protecting those who can not protect themselves. They have been labeled the good guys. Unfortunately that is not the case in every example.
Personally, I don’t expect the police to be the “best of the best,” especially given that what they do for a living forces them to confront the worst side of humankind on a minute-to-minute basis. If this hardens them, that’s perfectly understandable.
What I do expect, demand actually, that they not use excessive force on anyone, and treat all races equally.
This, btw, is not just the voice of kindness and compassion; it’s the voice of the U.S. Constitution, in particular the 14th Amendment.