On Batman and his moral code of not killing.

Killing is a pass of judgement that a person is irredeemable, thus if Batman kills he loses hope in humanity. In some form it is pre-crime solution: to kill is to prevent future crimes (it is done out of fear rather than hope) - he doesn't want to cross that line. Because then it becomes arbitrary (the future is unpredictable), and where does that stop? It's a VERY slippery-slope, especially with Batman's intellect.

Yes, in some iterations and adaptations Batman has killed, but I think the idea is bigger than that and those stories have been missteps and misinterpretations of the character to which Batman has developed. Batman wants to be more than a man, but not superior to everyone else. He wants to give a chance for redemption, not be a judge who gets to decide who continues living and who does not. It's about the concept of "there's always another way." He is allowed to believe in that, even though it might not be the most practical/efficient solution.

The universe is chaos, nothing is permanent and the possibilities are endless, and the only way to have something solid and stable in it (so as not to become insane), is to uphold an idea, to believe in something, to have a moral code, something absolute to measure yourself against and as for being human - it ultimately boils down to not to kill, or at least use it as the last possible measure (because you are not better than anyone else, but not inferior either - and that's why some heroes kill the bad guy when they try to shoot the hero in the back, Batman ascends even that without sacrificing himself.)

Also it's not Batman's job to kill say the Joker.. He doesn't want to kill him, if someone else does, then they should go for it themselves, though Batty won't like it. And he is not accountable to anyone/-thing else than his moral code, he has to hold onto something, to have a foundation and that code is all he has left.

That's how I see him.