I think this article is a bit misdirected. If a superhero like Superman is traditionally white, there's no need to purposely make him into a minority just for the sake of diversity. If some director has a clear vision, wants to take a huge risk and make him a minority and it turns out really cool, then I'm all for it. But it's not something anyone has to do.
My HUGE annoyance though is when a character is traditionally asian like Goku from Dragonball or that kid from Avatar the Last Airbender and they make him caucasian in the movie just because they think they can sell more movie tickets. I find that highly offensive and I think it kinda cheats the intelligence of the movie going public as well.