Who cares. Superman was never White to begin with. His ancestors came from Krypton, not Europe. He is an illegal alien, quite literally. The whole point of Superman is that White people can't solve their own problems, that they need an alien to come and solve their problems for them. Besides, superman was created by Jews Jerry Siegel and Joe Shuster. Superman was specifically created to corrupt White thinking by getting young, impressionable children to worship a superhero of an alien race.
In addition, the idea of a hero with a dual identity, one heroic and one mild mannered, was stolen from Johnston McCulley's character Zorro. Zorro is a true White heroic character. He is also a true Hispanic heroic character (albeit created by an Irishman), as Hispanics were originally White, and some still are.