Arizona is a stop-and-ID state. You don't have to actually show ID unless the cop has good reason to think you're lying, but if asked to show ID you have to give your name under Hibbel, and failing to give your name when asked for ID can be grounds for arrest (which is very weird, but that's what SOCTUS said) .
So the cop was being a jerk and probably profiling her. That happens. But he was also within his rights to stop her and ask for ID when he saw her technically breaking the law, and in response she had to provide her name. (And to reference a different thread, the fact that whites probably don't get stopped even though they could be is what white privilege is all about.) But she reacted very poorly, and under the circumstances I think the cop was within his rights to do everything he did. He actually showed more restraint that I expected from the headline, repeatedly telling her to put her hands behind her back and to comply. The only reason she ended up on the ground was because that's what happened when he tried to force her hands behind her back so he could cuff her. I don't know what she expected to happen when she was resisting arrest. And what did she expect passers by to do? Intervene and assault a cop? It's just a series of really stupid decisions and the weird belief that you can hector your way out of a police encounter by calling a cop disrespectful.
Like they say, you can beat the rap but you can't beat the ride. Much better to comply and then sort it out afterwards in the media or the courts.