If a car load of armed civilians jumps out of a vehicle with weapons drawn and approaches in a menacing manner, they deserve any lead thrown in their direction. If you're a cop, you'd better damn well look like one. If you're not dressed like a cop, you're a civilian. Anybody can say 'Stop, Police' while firing in your direction, and dodging bullets while waiting for them to show an ID is not a recipe for a long life.
Next time it might be the officer that catches the lead... for the safety of every other officer out there, they need to throw the book at these SOBs and lock them away permanently.