Where to begin? I'm in my 23rd year of full time LE. I make a point of NEVER getting involved with enforcement activities while on my own time, unless we're talking about a violent felony in progress...and since I also make a point of staying out of my jurisdiction while on my own time, the odds of me feeling compelled to intervene are very low. Another thing: PLEASE don't make the assumption that everyone who wears a badge acts the same way this putz did. Those who do were jerks before they ever put the uniform on! Quite a few of us go out of our way to treat everyone we deal with as we'd like to be treated, and that attitude has served me exceptionally well for all of my career. Meanwhile, I'd make a complaint to his department. If you make enough noise, they'll find out who he is and address what happened.
Seen on a bumper sticker: "Exercise. Eat right. Take vitamins. Die anyway."