People aren't angry because they responded to the call.
Watch this video in case you haven't:
https://www.cnn.com/videos/us/2020/05/29/george-floyd-kneele...
> How is the US a police state?
There's not a simple yes or no answer to this question. But if you sincerely want to understand where people are coming from when they make the claim, you ought to do some research.
I'll give you a head start. Try googling:
"police spying without warrant"
"stop and frisk"
"police perjury"
"police license plate readers"
"police phone data"
Also, check out organizations like the ACLU, EFF and many others who work very hard to prevent the US becoming a police state.