This version of Batman does not have a "no kills under any circumstances" rule. He sometimes kills people if he considers it necessary. If he did, the plot would instead be a slightly modified version, where he plans to subdue Superman and throw him in superprison or something to that effect. It wouldn't change the motivation though.
Yeah, but the issue is that he doesn't seem to have a meaningful value of human life period. He kills people less because it's necessary and more because things are just easier that way. Even his issue with Superman's threat is undermined because he goes out of his way to prolong the fight with him just to make insults. He could have killed in him the first two seconds of the fight by stabbing him with the spear the moment he got first gassed superman, but he decided he'd rather tell him how he sucks. If he truly believes that Superman is that kind of danger, and then why is he standing their talking? Everything that goes on in that fight tells me that his actual issue with superman is more how his existence is a threat to his ego than to the world. And you can't tell me all the super happy fun times he had with criminals couldn't have gone any other way.
In TDKR, Batman shut the program down and told everyone it was a failure because it became clear that it was possible to weaponize the technology. This is what I was referring to - he considered it too dangerous to have around despite its potentially vast benefits. People have mocked the line of dialogue about "if there's a 1% chance he's our enemy we have to take it as a certainty that it is", but I really don't know why, the implication of his reasoning is very clear and it is neither illogical nor out of character. What is out of character is that he's willing to kill both Superman and other goons in the film (at least - he doesn't pretend like he's not a killer but then kill people on the regular like in all the other movies lol), however that is not a flaw in his line of reasoning, but a different take on the character.
But he continued it in secret, iirc. I mean, that's why it was still around for Talia to take. He was working on it until it could be used without weaponizing it. If he didn't find a way, he was prepared to destroy it, but he hasn't. So he clearly believed it in, he just was going out of his way to do it safely. He was minimalizing that percentage of it being weaponized as much as he could while still going through with it, which is again the opposite of the 1% line he gives in BvS.
And while I don't really have an interest in defending Burton's films, in TDK trilogy, what he is opposed to being is an executioner, not a killer. That's where I think his no kill rule is probably depicted probably the best it can be in regards to adaptations. The only exception to that is Ra's al Ghul in BB, which I heard a few excuses for, but I never quite got over. But everything else, from the league headquarters scene, to Harvey Dent, or Talia, that's all him simply trying to preserve his life or the lives of innocents, and he accepts people will die in those kinds of environments while still doing everything in his power to not cause more deaths than needed. What he won't do is take it upon himself and judgementally kill someone simply because he thinks they're scum, like the farmer in BB. The fundamental function of Batman in the Nolan trilogy is to jump start the police and legal systems that have been bogged down by corruption and crime by suppressing organized crime enough so that the police and legal teams can get a foothold. So his kill policy makes perfect sense there, because it's not his job to kill or even save innocents or anything like that. His job is to make it so that the proper authorities can do
their jobs. So doing things like issuing death sentences is simply not his division and he takes no measures to make that decision.
That's as practical a interpretation of a cinematic batman as I've seen. Though I do find it funny that hollywood feels the need to make that revision in the first place. I'm not married to the idea, but it'd be interesting to see Batman with an actual no kill policy.
Please keep in mind my post was directed at whether or not the 1% line "made sense", since to me his line of reasoning is very clear.
The line of reasoning for that line is clear in so far that I understand why he is saying it, but that doesn't make it rational. Honestly, if nothing else, that line is a self-fulfilling prophecy waiting to happen. It's a line that denotes how far gone Batman is that he thinks that any measure of danger MUST be eradicated (though like I said, I'm not convinced that this is what is actually happening when the fight itself happens). It's a knee jerk reaction given by the paranoid and cowardly.
There's no question that Superman's power is something that should be assessed and in some way kept in check. But intentionally making Superman your enemy for the mere fact of his existence instead of....you know, assessing who he is, finding out what he is about (which is only more likely to give you ways in which to keep him in check anyway), is just stupid. It's an immediate jump to the nuclear option that doesn't consider more peaceful alternatives. And even the movie acknowledges that by the end. Batman finds out that superman is an actual person with a mother, named martha, like his. If the mere revelation that Superman has human relations blows his mind so goddamn much that he does a 180 on his stance, and is now okay with letting the living thermal nuclear threat exist, it shows how small minded his viewpoint was.
That's the major difference here. Yeah, threats are threats and only an idiot would ignore them. But there is a difference between dismantling a machine and murdering someone because you're afraid of them. And there is a major difference between 'keeping a threat in check' and forcing antagonism because your afraid of what someone might do. The line is being mocked not because it doesn't make sense for why batman would say it, but how fucked his mindset is. And you're right, in other continuities, batman performed similar actions of threat prevention and contingency planning, but for various reasons, the actions there were made nuanced by Batman willing to give others a chance to prove them wrong or taking safety measures while still going through with it. BvS Batman stewed about how to murder a guy for 18 months, and then backtracked when he discovered information that he could have found out if he did the most meager amount of research on Superman at all. Plenty of Batmen have taken precautionary measures, but BvS stands out as being stupid about it.
_/¯ sure