OBL was not in 'criteria' of "unarmed man" - so can cancel second assumption of argument. OBL was an evil, world-class terrorist - who was responsible for the deaths of thousands and more - of innocent people. Judgments were made - on our behalf; by those we ascribe power to. God will take care of the final judgment - on OBL's behalf.
That said; how can/why are, Liberals so freaking, Liberal stupid? No question; this ideology, unequivocally, cause brain damage. No other rationale to explain the vacuous stupidity so offered by the Archbishop of Canterbury.