Which is fine. DC keeps Joker alive cause he makes money. I can accept that even if I don't like it. It's when they try to wring cheap drama out of it that people become annoyed by the existence of the "no kill rule". If you're not gonna kill if your cash cow, don't insult the reader's intelligence by acting like there's some moral dilemma in killing someone as monstrous as that.
Who's saying he has to kill everyone? It's not like he won't run into some villains that won't require lethal force to stop.
Another thing that's also glaring is that Bruce is the only person who is safe from the Joker's cruelty. He'll never be shot and crippled by the Joker or beaten to death with a crowbar by the clown. But everyone else is fair game. Thus it makes the entire battle nothing more than a sick game between to disturbed individuals with every Gotham citizen caught in the middle.