Batman doesn’t think he is anyone’s judge, jury, or executioner. Also, he is afraid that if he kills people he will go crazy.
This is actually not not quite true, or at least it is misleading. It is not that he fears that he will “go crazy”, it is that he fears once he decides to go down this path he will feel too tempted to go down that path again and again. Then he may be tempted to take the “easy” way out and kill again, possibly going out of control. This was a major theme of the “Venom” arc, where he was hooked on the Venom drug and became overly aggressive and brutal. He was not killing people as such as I recall, though he was being far more violent then was really justified in order to solve the crimes in question.
Almost nobody would be able to really stop him, as he is a force very much beyond the control of Gothams legal system. If he goes rogue, they will find it very hard to stop the words greatest ninja and detective. What they going to do, call in some other member of the Batman family? Assuming the “Batman” in question is Bruce Wayne (yes there have been others, including Dick Grayson) for prolonged periods, almost none of the other Batman Family heroes are capapble of stopping him. What are they going to do, call in Superman? Bring Green Lantern (Alan Scott) back to Gotham?
What puzzle me is that some of them, like Batman, even reluctant to kill in self-defense.
See above. It is not that he has a problem with killing in self-defense, he has a problem with killing except when he considers is abosultely neccessary. Despite popular misconception, he has killed people before, quite on purpose. In one story, he deliberetely threw a cult leader into the hands of his disillusioned followers, intending that they rip him to peices. In another story he left Ra’s Al Ghul to die in an explosion, knowing that this would happen. In I beleive the same story, he kicked one of Ra’s Al Ghuls followers in a fashion that would clearly result in his fatal electrocution, in order to save anothers life. In “Final Crisis”, Batman takes up a special *gun* in order to try shoot Darkseid so as to prevent DS unravelling reality.
He does kill in self defense of his own life, or that of others. As a last resort, when no other methods are reasonable. Being the worlds greatest expert in physical combat in the DC universe, there are few few cases where it is neccessary to kill someone in the situations he usually finds himself in.