I do in fact hear the weasel words (oh, but he had drugs in his system therefore he was more susceptible blah blah)...but...if the thug hadn't been kneeling on his neck for 9 minutes straight, then those susceptibilities wouldn't have been triggered right then.
I'm thinking English Common Law here from which much of our jurisprudence descends; you know, like the driver in the getaway car being liable for murder if the gunman in a bank robbery shoots someone, that kind of thing.
It's not the same situation but the same "where does the blame really lie" kind of thinking.
I am maybe more logical than you.
I wait for ALL the facts to come in.
Then I determine if I think the cop should hang and if I should go burn down the town.
But if knee jerk reactions work for you then stick with what you know.