The counter argument to that one about levelling the playing field would be that, if you just rely on "black", defined on some arbitary decision as to how "black" someone is, you'd find yourself discriminating in favour of Colin Powell's children over the children of some poor white sharecropper. And that's just the thing that gets used to discredit the whole idea of positive discrimination as a way of levelling up the playing field, because in that particular case it has the reverse effect.

So to be fair and effective that kind of thing has to be done in a way that is much more sensitive, and relates to the actual situation of the people involved, rather than following these broadbrush definitions.

When people are getting persecuted on grounds of "race" it's necessary to take account of it as something that exists in the minds of the persecutors, but that doesn't mean adopting it. Otherwise it could imply refusing to help some victims of persecution because they were seen as belonging to the wrong race. And of course that does happen sometimes.

"Biogeographical diversity" is a term that sometimes gets used to talk about the way that people (and other animals, and plants for that matter) do vary, but do so in a much more complicated way than implied by the term "race". It's a bit of a mouthful though.

But in fact it's quite possible to manage without actually using the word "race" - if someone is persecuted for being a Gypsy, or a Jew, I can't see how it helps in fighting that to adopt the language of the persecutors and talk about them being persecuted for being a member of "the Gypsy Race" or "the Jewish Race". You don't have to believe people persecuted actually are witches to fight against the persecution of witches.