i still don't understand why superman and batman are fighting
its actually a fairly common trope in the DC universe. the most famous time they fought was in Frank Miller's comic The Dark Knight Returns, which is a heavy inspiration for the batman of this film. theyve also fought in the Justice League animated television series and Justice League: Crisis on Two Earths, and the game Injustice: Gods Among Us, and many other times in other comics/movies/etc. usually, these plots examine the limits of supermans moral standing, and explore the potentially dangerous realities of a superman "gone mad." sometimes superman goes mad with grief and begins killing or lobotomizing villains to keep them at bay for good. he becomes authoritarian and cruel. batman, as supermans foil, is usually the one that has to stop him.
i dont think this superman is like that. i think hes a good person. but after the fight with zod, its pretty clear that he's very dangerous- he wasnt directly responsible for most of the destruction, but he was intimately involved, and thats enough to raise some eyebrows. you can hear lex luthor talking about devils coming from the sky, and you see a bunch of people who appear to be zealously loyal to the idea of superman (the soldiers, the people at the festival, etc), and you see that there are some people who don't like him (the go home chants, the false god graffiti). so he's a pretty polarizing figure. there isnt a consensus on whether or not its ok that hes here. i think bruce is worried that superman will inevitably cause more devastation no matter what, and he needs to address the problem once and for all, so he's going to go one on one with supes and beat the truth out of him. but i think there's something to be said for the title- it isnt "batman vs superman," its "batman v superman," like in a court of law. it implies a conflict of ideals or ethics, and the rest of the title, "dawn of justice," is pretty obviously a setup for future justice league stuff, so we know they're gonna work this out somehow. i think lex is gonna end up being the main threat here.