Great movie ... The ones disappointed with the movie are the ones who were expecting it to be based on the same superhero lore that the hero comes from the sky and saves the day from a villian and then everyone on the planet happily accepts him . But this story is based on real world setting. if one day a superhero falls from the sky , this is general reaction that some will consider him as a God , some will be jealous , some will fear what about humanity if one day this powerful man snaps.
That exactly what Snyder potrays , Luthor is just a jealous guy because he was the brilliant who should be saving humanity and not some overpowered alien and batman is scared that what if this alien turns against us . But Supes is above all , he is all about hope and helping people which directly clashes with Batman's view of delivering justice with whatever means necessary. But the only fallacy is that stopping the clash with one word " martha".
Overall it potrays different spheres of human thinking . Would love to see Snyder's version of what happens when Superhero come in real World and not in some marvel world where a Portal opens in ny sky and no enquiry is followed up