I suppose if the video was of a guy jay walking on an empty dirt road, then perhaps you have a point. On the other hand, when a guy directly attempts to run over another police officer while nearly getting a number of others killed, yeah I'm willing to let them decide which homicidal nut case needs beaten.
So if you think they were justified, why do you think they supressed the video for a better part of a year.
Also, as I am pretty sure I mentioned before...the man got 20 years for his actions. Id rather have the courts and a jury of my peers decide my fate than potentially being killed by police after I was lying motionless on the ground.
Cops are trained to enforce the law, keep the public safe, and be a first responder. They are entrusted with a great amount of responsibility in the use of lethal and non lethal force.
Once the suspect is no longer a threat to anyone, that aspect of the job is done, it is time to move into the role of first responding medics. There have been more than a few cases where police have been forced to shoot a suspect. Once the suspect was down, and no longer a threat the police, the cops helped treat the suspect for thier gunshot wound. Not walk up to them and inflict further damage after the suspect was down.