OL wrote:
That was such a b-list Justice League back then
It's a dream sequence, or some kind of "worst case scenario" thing going on in Batman's head. It's imaginary. That's why it looks all post-apocalyptic, and Superman has soldiers bowing down to him; this is what Batman thinks Superman could eventually bring about.
That's what I'm thinking, too. I suppose that's gonna be pretty early in the movie, maybe it'll even start with a shot of that wasteland, Batman fighting a horde of infinitely spawning Superman minions, then being overwhelmed and captured. Especially the scared look on his face while Supes is walking towards him makes me think it's a dream. Not that it's not reasonable to be scared of Superman, it just doesn't really suit Batman to show it like that. And in your dreams anything can evoke a deep fear within you.
The reason for this scene is probably to make viewers relate to and connect with Bruce's emotions and fears concerning Superman, to show that he's not simply being a jerk towards Supes, but that he's actually being haunted by the thought of the almighty alien doing great harm to humanity, which he's been trying to protect ever since his parents were killed.