According to the National Sources of Law Enforcement
Employment Data, Revised October 4, 2016 (sorry, that's the most recent official report I could find), there are 17,398 policing agencies in the US. That leaves 17,397 police agencies that have not approved "killer robots". Once such a robot is used to kill someone, let's see how long that ruling will stand.
I'm not saying that the ruling is a good thing, just that your reaction to it has NO PERSPECTIVE.