Do you honestly think this would have happened if Leake had cooperated fully with the cop? If your answer is no, then objectively Leake contributed to the situation. You seem to be equating "contributing to the situation" with "being to blame for the situation." The two are not the same thing. Objectively, Leake contributed to the situation. In this case, there's absolutely no way his contribution justifies the cop's response - that much is beyond dispute IMO.
It's pretty simple, really, the vast majority of the time if you don't provoke a person, that person won't attack you. Does that mean that if you provoke a person and he attacks you, then you're to blame for the attack? Only if the provocation was severe enough that the person was reasonably afraid for his safety (or the safety of others). Does that mean that by provoking the person you contributed to the situation? Of course!