If Ben Affleck's Batman is not afraid to kill people then why is the Joker still alive? Seriously, he has no problem wasting nameless goons, or even the KGBeast holding a flamethrower to Martha Kent... So, why does he let the Leto Joker continue?
sharefor potential sequels... these comic-book movies are like TV series... they can't get rid of big, key characters easily...
Just enjoy them for the spectacle... there is nothing else to see there, nothing to read into, no meaning... it's just cartoons...
I'm not trying to defend the film but this is my take. I think we're suppose to infer that his abandonment of his no kill policy is both new and visceral by the time the film starts. He's lost every ounce of youth and vigor in him and is now a tired, jaded old man whose morals are easily compromised. But that doesn't mean he'll actively go out and kill people. Killing is a reflex. Personally for me though, starting your adaptation with a different or changed version of the character is strange story-telling.
A bigger question, if Cavill's Superman is willing to kill, why doesn't he just rip off Lex's head?
The whole fun in adaptations is being presented a different version of something you're familiar with. Plus it's not like we haven't seen shades of these characters in the comics.
Superman killed Zod cause there was no other option, not just cause he could. His reaction afterwards showed it was not something he wanted to do but Kryptonite was still undiscovered along with their vulnerability to red sun. So where on Earth would they be able to detain Zod?
Couple that with how half of the world disliked him and now ask yourself again why Superman didn't kill human Lax Luthor.
I agree. Also what we see in BvS is a Batman that is first lost and is simply on the wrong path (as you describe), but during that story he is found again and comes back to his old ways; he last line is: “I failed him in life, I shall not fail him in death”.... in other words, he is in the end not a killing vigilanty anymore and this perhaps answers the OP.
Also obvious in his rescue of Ma Kent. Here his fighting is perhaps very brutal, but not lethal - at least in intention. He disarms them first, destroys their weapons etc. His fighting style and approach is visibly different from his approach in the beginning of this film. The scene where he shoots the gas tank to save Ma Kent is directly lifted from Millers comics. Except in Millers version, Batman headshots the bad guy... the fact this scene deviates so fundamentally on only this is to show us (I speculate) that he had changed his old evil ways...
A bigger answer; Cavill's Superman does not kill because of his experience with Zod. The remorse and pain he experienced here taught him his place in the world. He is no executioner, he is a servant of justice (and beside, ripping of Lex's head would have solved nothing and possibly indirectly killed his mum)
Killing is not an option but an unavoidable consequence after YEARS of fighting a one man war against gun wielding mercenaries in the real world.
In a world with a human crocodile, gods, and aliens walking around, how long do you think they would be scared of a human in a bat costume with a no kill policy?
Joker likes that he broke the Bat and the ultimate punchline for him would be getting the Bat to kill him. Showing everyone he is no better.