I think I've blundered into three arguments here - the artistic, the real, and the ideal.
In terms of the artistic argument, I have none. If the point of the fantasy is to comment on some present aspect of society then sure, have at it - white vampires; no problem. An army of them. An empire of them. Artistically, it's all good as far as I'm concerned - counting, as I do, Iron Sky as one of the guiltiest of my guilty pleasures.
In the real world, yes, it's a mess. A Gordian Knot of timelines so closely entangled that they're choking each other. There's very little reason in it, and way too much blind faith. Too many people too angry, or too afraid, to do anything to even consider the galactically distant possibility of getting ready to entertain the notion of maybe pondering the chances of an initial approach to the idea of thinking about maybe letting all this crap drop and moving on, for f*ck's sake. So instead they continue to shout at one another, and over one another, and past one another. And reason battles emotion on yet another front - which might just be the war mankind's been fighting with itself since achieving self-awareness. It can't be solved by reason alone and neither alone by emotion.
Lastly, my old Mistress Nemesis the Ideal - or the ideal as I see it. "No, no, no," I cry, "look at it this way - if you look at it this way, it makes sense." Then you all tell me to f*ck off and hilarity ensues - but hold; not this time. Just stfu and listen, because if you look at it this way, it actually makes sense.
If I had a magic wand which could, in the most ideal of ideal worlds, eradicate racism then I'd use it. I think it's counterproductive, it's dangerous, it's barbaric and it's immoral. But I can't banish it from the world. What I can do is try to banish it from my world. This leaves me open to the criticism of ignoring the realities of a subject, often entirely justified as that's exactly what I am doing - trying to dig down a little bit further, to take things apart. Here, I was faffing about trying to decouple "white" (and "black") from "oppressor" because the colour of an oppressor, on a purely intellectual level, is of no consequence. The bullet doesn't care whose finger's on the trigger. To decouple one from the other seems to me a good way to focus on what it means to be an oppressor without the distortion of a coloured lens of any hue. Which is not to say that racism is not a driving factor in the real world - just like geography, sociology and economics - but the trait of oppressor, whilst no doubt influenced by many factors, stands apart from them all; even racism, which is an evil unto itself.
TL;DR - Whilst race may be a factor in oppression, oppression is not always a result of racism and the human race will continue to war upon itself as colour agin colour and sex agin sex and me agin thee until The Blessed Day when Lord Sir Most High John Lennon is made God of Earth and Imagine the global anthem. Then we might have a chance.
STL;SDR - Racism bad, oppression worse.
