Ok, here is my two cents: I wasn't there, I did not see what the jury saw, so I cannot address what the jury got to see and what they did not see. Understand that in any jury trial, the jury actually only gets to see part of the evidence, never all of it. The Grand Jury gets to see it all, if it is done right and it so seldom is unfortunately.
The video is horrific, just watching the video you cannot come to any other conclusion.
That being said, where is the rest of the context? What was the call, what were the facts put out by the dispatchers to the officers who were responding? What did they see from citizens at the scene and what were they told by citizens at the scene?
I have been in a police shooting, I have almost shot several other people over the course of 23 years, I have been stabbed by a guy we were fighting (I was lucky, he hit my vest so I survived). I have been on the receiving end of garbled, overly excited dispatch transmissions, I have also seen the chaos at situations where you have seconds to make a life or death decision.
Stuff like this, makes it really hard to defend, and I am not trying to defend the officer who did what he did. The ejection port "art" is completely unjustifialble, and just plain stupid. The book Rise of the Warrior Cop, is good, but it has blind spots, the "Us vs Them" mentality has developed since the Clinton Era where the Left has consistently demonized cops. How often do you a positive portrayal of police in the media? Seldom if ever.
I have had guys approach me in felony situations screaming things like "Don't shoot me, I give up", and then as soon as they get within lunging distance they attack. I was told by an old veteran cop (Texas Ranger), that you use short (3-4 words) sentences, loudly, and repeat it. "Stop!" "Do Not Move" "Lay on the ground!, Show me your hands", because studies have shown that people remember, and react to short authoritative statements. It has worked for me, I have not had to shoot anyone since 1997. The guys laugh at me and tell me I have "the voice of Satan" when I am giving commands, because people tend to obey them.
All that being said, the video is bad, really really bad.