I just watched this movie a few days ago..
The crips shot at Denzel because they didn't know him, and Macy Gray was shouting that they weren't the cops and had stole her money...plus, look at the car they were driving and they didn't have any backup...it was easy to blast and react without thinking much just based on Sandman's girls screams...
and the bloods kept it real cuz they all knew him and add to that the fact that he had helped a few of them stay out of trouble. "Thanks for lookin out for the homey," one blood said earlier in the movie if you can remember.
On the birds note, I've heard about people "flippin birds" to show their power in the hood to have the birds at their command...I don't believe that had anything to do with Denzel bein around. (plus it tells a little bit about the birds in the documentary)
I have a few homeboys that lived in the jungles and it's right by Crenshaw (behind it I believe). Most of Crenshaw is Crips but people in the jungle mostly go to a different school (forget the name) and I heard there is funk there all the time.