Your narrative assumes facts not in evidence. Attacking a cop does not require a reaction of lethal force as marc's evidence shows. Nor is it clear he ran towards anyone else. So the police did not have to assume any violent intent.He attacked the cop. He then ran towards other people. The cop has to assume violent intent.
Attack a cop with lethal force (and a sword counts as such, even if it doesn't have an edge) and the reply will almost certainly be lethal force. Some examples where the guy was *NOT* a threat aren't rebuttals.