Or in democratic societies we can insist that our "public servants" actually serve the public interest of law and order rather than merely using it as a pretext to be able to commit their own violent crimes.

Your rationalization is nothing more than a product of a failed society. Bringing it up as pragmatic advice might make sense, although still not for this incident where the "offense" seems to have been merely stopping a car on the side of the road. But invoking it as some universal value of "what ought" is a pure crab bucket mentality.