Judging by the video, he wasn't the only one having a bad day...He had a very bad day, apparently, It happens, and I'm more sympathetic now that I know more. I've had similar experiences (though we did not carry firearms inside the prison), and on my best bad days I'd think ahead and let my team members know I was not up to snuff.
Someone would invariably take the lead. Everyone understood this kind of thing, it happens to everyone. Night shift alone beats people up pretty good.
I would hope we could all agree the cops were dropped into a very bad situation, and maybe the one guy could have handled himself a little better. He said as much.
On a good bad day you recall what you should do vis a vis your team. On a bad bad day you don't.Judging by the video, he wasn't the only one having a bad day...
I don't know what was in his lunchbox that day, but I'm not convinced it matters. The guy had a gun and a badge of authority and he abused both. Police officers should have aptitude and training, and not just attitude and a gun. If he couldn't keep a level head with a group of teenagers, what could you reasonably expect from him in a serious confrontation?
EDIT: As you alluded, he should have made it known if he was not fit for duty on that day for whatever reason. It's on him, as it would be for an airline pilot or a surgeon, or any other job where a very small difference in performance can result in a very large difference in outcome.

Affluent? The demo is 65% hispanic.
I have friends who live in Dallas and they tell me that area is affluent.
Affluent? The demo is 65% hispanic.