That was pretty bad, usually I will jump on the officers side pretty quick, but that was very poor judgment on the officers part. Granted we don't know the whole story, and maybe some other factors were involved but trying to dig up more info from other sources weren't much help. The article made it sound a lot better than the video portrayed, which of course was clipped for the story, which I never like.
I'd say the stop was good, drawings his weapon was acceptable, but not letting Moats go even after even the nurses were informing the officer about the situation, I would think is very poor judgment. If the officer heard the story from Moats directly while contacting him, then just ran his ID and SBC'd it when it came back clear, I don't think it would have been an issue. A bad deal for sure, and I feel bad for Mr. Moats, though I would say that calling for the officer to be terminated is not the right thing to do at this point.
I am sure the internal investigation will be fair and find out what he was thinking, and perhaps there was something more to the story that's being left out. A lot of training goes into becoming an officer and I would imagine Dallas is one of the better departments in the US, I would hope that the officer has a good explanation for his conduct. I suppose only time will tell.