You assume the police had all the facts at their fingertips. They did not.
It looks to me like they double and triple checked their facts before releasing the. To blame the police for the actions of the media is uncalled for. They have no control over what the media is doing. I would commend the police for making sure they stood on solid ground rather than react. To assume that if they had blasted unsubstantiated facts over the airwaves would have stopped the rioting is totally naïve. The rioters and racebaiters were going to do what they did whether the officer was in the right or in the wrong!
I can't see how a bloodied cop's face wasn't known within minutes. I understand many facts were not known on the first day, but this is not one of them. A policeman being attacked potentially would have been one of the first facts reported on a call about the situation, and if not it would have been immediately clear the moment others arrived on the scene. He clearly needed immediate medical care.
I understand there is no rational thought behind the rioters and looters, but to the community as a whole and the nation, this information should have been out within 24 hours as a key piece of information. As I mentioned, I have solidly conservative friends who 4 days ago were convinced this was a cop gone bad shooting an unarmed kid. There are millions who still have no idea the police was assaulted by the guy. The narrative is hard to change.