I moved out the US just for a few years. Almost a decade later I still haven't returned. And when I seriously contemplate picking my return date I see events in the news like Michael Brown, Tamir Rice, Sam Dubose and think why should I move back.
Wow you cherry-picked 3 examples (see confirmation bias) and thought stuff like that happens to every single person in America pulled over by a cop (in a nation of 300M+)?
It happens all the time in the Bay Area. Pretty much every week I have friends who are either witnesses or were very close to shootings or situations with police brutality. Hell I stayed there just for a few months and I saw firsthand a cop restraining a person with a boot up their face. I had never before seen anything like that, and I've been to some pretty violent places.