All he did was push her, somewhat hard, and she fell to the ground. Just because she flopped like the bitch she is doesn't really mean shit.
I guess what is really stupid about a video like this can be boiled down to a couple points.
1) Why does age matter? Age is Monday quarterbacking - at the time it is completely irrelevant.
2) These videos get a lot of attention because the anti-police crowd love them (or hate them?) to death. It is that needle in a huge fucking haystack that, to them, goes to show the police are corrupt, abusive, you name it. How many police interactions were there that day in Phoenix? In Arizona? In the country? The anti-police crowd love to ignore the good/useful/casual/non eventful shit that goes down, but will bring a video like this up time and time and time again.
If you don't run (or obviously walk away) from police after a physical altercation like that you aren't going to get dropped