And when race matters to white people, to stamp it out.

That particular sentence was vague, I admit. What I meant was that people are trying to stamp out skin-color-as-identity in white people (the Klan being a far extreme of this) but encourage it in black people.

I'm not sure I understand the equation you're making between acknowledging in fiction that non-white people exist and "encouraging race to be important"

What I'm saying, I guess, is that having a double standard, even if there are good reasons for it, causes more problems in the long run than it solves. I'm happy to see non-white people in SF/F; being drawn out of myself is why I read fiction. But I reject Noles's reading of ordinary, racially unspecified characters as "generic white" because they're not specified as being otherwise. If she can't imagine them with dark skins, that's her problem, not the writer's.