I have rather mixed feelings on the whole who owes respect to whom issue. On the one hand, I do believe that people paid to deal with the public (I hate the term public servant) should always try to show respect for members of the public when they interact with them, and there is nothing saying that members of the public must show respect back. Of course, that's only if the methods used to show disrespect are legal. Spitting on someone can actually get a person charged with battery (or assault if you spit at them and miss.) On the other hand, if a member of the public doesn't show respect for one, or all, of these people, they shouldn't be surprised when they aren't shown respect in return - especially if their methods of showing disrespect are not legal.
In this case, I really didn't feel she was being very disrespectful. She answered his questions and never used profanity until he got physical with her. He had no valid reason (at least not an apparent one) to order her out of the car, to grab her, or even to insist that she put out her cigarette, but once he did tell her to get out, she was legally obligated to do it. I definitely don't believe he had a valid reason for threatening her with the taser. I believe that he could have been sued for false arrest if things wouldn't have gotten so out of had.
Moo