> But I believe I am justified in that because whiteness is not an ethnicity, it is the practice of denial of ethnicity.

I fundamentally do not understand what that means. Surely I don't have a choice but to be white? What am I denying? It's true that whiteness is not an ethnicity, since Russians and white Americans are surely ethnically distinct - more so, I think, than white and Asian Americans or white and Asian Russians. But beyond that I can't make sense of your sentence. I wonder if it depends on a particular national interpretation of "white" that cannot be accessed by all people who might want to describe someone as "white". But it seems opaque to me.