“Warrior mindset”. When you’re trained to assume that everyone you interact with is a lethal threat, you tend to react as such.

They go around barking orders at people who haven’t done anything wrong because they look “suspicious,” escalate what could otherwise be calm encounters by showing up to everything armed to the gills, make it clear they can’t wait to use force against persons and property, demonstrate a consistent us-vs-them mentality that looks the other way for clear cases of corruption, commit brazen armed robberies under euphemisms like “civil asset forfeiture,” bypass policymakers wherever possible and lie to them when they can’t, and then wonder why some people don’t like them very much.