I haven't read the rest of this thread, but a few thoughts:
1) That video was hard to watch - senselessly sad, and I am glad that these officers were fired after a proper investigation. It's mind boggling that this happened ... well, sadly it isn't. :/
2) Even taking the obvious moral issues out of it, what in the HELL did that officer think would happen?! Has he never turned on the news regarding his field of work in the last several years? The guy was wearing a body cam, for Pete's sake. Even if he weren't an alleged murderer, he is a HUGE idiot.
3) It really is sad that a minority of cops gives so many a bad name, and I hope that this picks up a trend of prosecuting actions like this to the fullest. Every cop I have interacted with or seen here in Chicago has been so nice and helpful, and a very large minority of them have been Black. I can't even imagine the complex feelings they're feeling right now.