There was an altercation (this often angers cops). Brown fled. Is it possible that Wilson was angry? Why would Brown charge an armed officer after fleeing him?
None of this demonstrates anything conclusively. It's reason for us to have some humility and admit that we honestly cannot know what happened.
Yes, altercations often anger or result form the anger of all parties involved. And?
Yes it was possible Wilson was angry. What is the evidence he was angry? What is the relevance of if he was angry? He was also probably afraid, and that
has evidence. Also, what actions were taken has evidence.
Why would Brown charge an armed officer? As you say, I can't be sure
why but I can say that the evidence indicates that
he did. Was he angry? Probably. Was he afraid? Very probably. Those are reasons to charge. What do these probabilities have to do with an indictment? Very little. What one can prove
in this case with evidence is the entire point.
We can know to a reasonable degree of certainty some of what happened, and even more about what almost positively
didn't happen. This has nothing to do with humility, but following the evidence. Even more than that, recognizing that even is the case is
exactly as you say no provable then the grand jury is
exactly right to not send it to trial. You don't send unprovable cases to trial.
As I've said before, I think the police of Ferguson showcased some major abuses of power in their handling of the initial protests, aggressiveness and arresting of journalists, of their no-fly zone implementation, and a litany of other ways. However, there isn't quality evidence that Wilson committed a crime, shot Brown in cold blood, or even killed him in hot blood. The injustices of the police here and elsewhere don't mean that Wilson was in the wrong.
EDIT: From your above post it looks like we are largely in agreement, except that I can't see how this specific incident is useful in the discussion of police us-vs-them besides examining the
reactions to the event.