I'm pretty sure I knew through popcultural osmosis before I ever saw any of the films
Some people weirdly don't connect fictional scenarios to real life analogues though. Like in the Oz books, a princess is kidnapped and forced to grow up as a boy. Some people don't see that as a transgender character because it's a fantasy scenario. Some people don't see Superman as an immigrant because their brains just don't connect a science fiction situation with an alien to immigration
I'm saying that when he's an adult, his origin is provable. In some of the films, Lex Luthor finds the proof
I think Diana is an illegal immigrant too
They claim that they don't want movies talking about politics, but I bet they'd have no issue if the movie was anti-immigration
There is proof of his origin, that hologram of his father that explained it to him
Do the people complaining about it know anything about Superman? If you didn't think Man of Steel had commentary about immigration, you either didn't watch it or you're an idiot. I wish there was some way we could enforce a rule that you have to know something about the franchise you're commenting on.
Maybe they'll set it loose in the concentration camps
So whose hands is the blood on?
They got rid of birthright citizenship so it doesn't matter
With parts from tanks that died of old age
And his supporters pretend to care so much about protecting children
In one of the movies he's a toddler when he comes out of the pod