Yes

Batman's play at a moral high ground is nice and all but in the end if he has the choice to finally end the Joker and refuses to do so constantly, then does that make Batman an accessory to murder especially since he knows that Joker will escape and will kill again. This is not the case of him killing a suspect or someone just plain sane but rather killing a straight up psychopath who, as the plot demands, will never change. This is not the real world and the Joker is not a man who made a mistake and may in time come to repent. The Joker knows exactly what he is doing and loves it too much to ever stop doing it. The only true way to end the Joker's reign of terror is to end the Joker himself.