I can see where it comes from, US officers are armed, and need to be so because they frequently face armed criminals. They have to deal with a different situation. The problem is that those members of the US public that are not armed and actualy have no intention of criminality, or if they do in a minor and non-threatening form, are being dealt with by armed police officers expecting to deal with armed violent thugs. That's a recipe for utter disaster.
There's no easy answer to this. It's right to support police that have to deal with life threatening situations daily. But equally the non-violent public do not deserve to face potential threats to their life and violent coercion in routine interactions with law enforcers.