The video you refer to does not show what happen before he was put on the ground.
This thread shows the video of before.
What I posted is the raw video of the incident everyone is upset about.
None of the killers or accomplices (lookout / muscle) are showing any disheveled hair or clothing, no heavy breathing, no signs of a struggle.
And the knee on the neck is long after he is on the ground and cuffed, and after bystanders are shouting "you're killing him" or words to that effect.
This was in real time, not staged by lefty camera crews.
Deadly force is disproportionate once the guy is cuffed, on the ground, and not moving.