"I stopped him for not wearing a seat belt, and when he exited his car to hand me his registration, I thought he might throw some broccoli at me. So I beat him with my baton and pepper sprayed him."
That's just not a good enough excuse.
It's a good thing that police often video/audio tape their stops. Sometimes they help prove that a motorist is acting unreasonably. Sometimes they help prove that the officer is doing so. Here's a potential case of the latter. The officer started out very nicely, asking "please" and doing a good job. But then the motorist starts getting the treatment.
For example, when the motorist complains that his handcuffs are too tight, the officer says: "Well, you know what, that’s part of not going along with the program." The officer here was unhappy that the motorist didn't get back in his car like the officer requested, whereas the motorist wanted to eat his broccoli on the street during the stop. You wouldn't think that a minor dispute like that -- with no threats of force whatsoever -- would lead to a confrontation. But it did.