I live six miles from this. Local news has portrayed a much fairer picture than national news. The concept that the national media doesn't want to upset the populace is laughable. They have blown the whole situation well beyond what it is.
As far as your argument that he should not have shot multiple times... If a guy that big is coming after you and shooting once doesn't stop him and he continues to come after you then you continue to shoot until he stops. The officers version is that that is what happened and if the evidence supports that then multiple shots are absolutely justified. If Michael kept coming after him the officer probably thought he either missed or hit an area that did not convince Michael to stop. Unless the evidence says Michael was lying prone on the ground and then shot several times I'm not certain what anyone expects. Would you fire one shot and when the huge guy charging you doesn't stop just shrug your shoulders and say 'oh well, I tried. Guess since the first shot didn't work I'll just let him have my gun to do what he will with it.'?
As to your last question, if in the hand to hand scuffle you go for the officers gun and then you come at him and are quite large enough to physically overpower him and take said gun by force then, yes, I think it does justify you being shot.