And I think it's telling that you think the only reason to do it would be to make a political statement.
Not that you're alone in thinking that. But it's like, say Samuel L Jackson playing Nick Fury (who in main Marvel universe is white)*. He was a good fit, he did a good job, and why not?
Daniel Radcliffe didn't have green eyes, though Harry Potter is repeatedly said to. (Like, seriously, every book)
James Bond's defining character isn't that he's white, it's that he's British. He's just white because to most people that's the "default." It doesn't really matter either way what his skin color is.
And before you retort, "So if it doesn't matter, then why should he be black!?" the answer to that is, because if it pisses people like you off so much, it might be interesting to try.
*Yes, I know that the Ultimate Nick Fury is black and looks like SLJ. The point still stands.