The police who are always allowed to investigate themselves will always exonerate themselves.

Until we have citizen staffed boards of inquiry this will go on and on and on... And even then I'm not sure the problem would not remain.

Juries of citizens routinely exonerate the police in the most egregious cases.

The police are trained to instantly escalate when encountering any resistance. Resistance is to be met with overwhelming force.

He resisted. They met this with incapacitating force.

The video starts once they'd cuffed him. What happened before that? He was clearly taken down very, very hard and was already badly injured. There is no video of what happened in the van when he was most likely struggling in his restraints due to his agony. So, they stopped and forcefully further restrained him. I can imagine he might have been screaming so that a nice quick punch to the throat to shut him up might have been in order.

Again, the injuries themselves show that excessive force was used. To contend otherwise is absurd.