I think people just want a less band aid solution to the Joker and other Batman villains. They keep escaping prison, keep killing, and Batman just keeps putting Joker back in Arkam Asylum despite it apparently having more holes than swiss cheese. The death penalty apparently doesn't exist in the D.C. Universe, which makes it absurd that Batman just won't snap his neck. For fuck's sake, with everything the Joker does he could do it at random during his hijinks and there's a 50% chance he'd be able to get off on a self defense plea.
The problem is just that the Joker will never stop killing and killing is presented as the ONLY way to really stop him. And since no one else seems to be physically capable of doing it, some people just want Batman to get it over with already. Or at the very least STOP CONSTANTLY SAVING HIM! Christ, Bats is probably better at saving the Joker than he is his own friends and family.
The problem is just that the Joker will never stop killing and killing is presented as the ONLY way to really stop him. And since no one else seems to be physically capable of doing it, some people just want Batman to get it over with already. Or at the very least STOP CONSTANTLY SAVING HIM! Christ, Bats is probably better at saving the Joker than he is his own friends and family.