What you are pointing out is that there seem to be a huge problem with the quality of the police force in at least parts of the USA. I might be naive, but I refuse to believe that the US is such a violent country that the number of people killed by the police is justified. What the US deserve is a police force that is better trained, less militaristic and skilled in deescalating confrontation. It might be a bit more expensive, but it should be worth it.