If ethnicity doesn't exist or is irrelevant, ask yourself whether or not you'd be comfortable applying for a job as a "hispanic" or an "African American" if you're white. After all, if ethnicity "does not exist," saying you're one ethnicity or another isn't really lying, is it? It's no more an expression of reality than saying you're "non-Hispanic white," correct?

But if you're not comfortable with that lie, as I'm not, then you really DO belong to a legitimate ethnicity, and in this country belonging to the ethnicity "non-Hispanic white" can only hurt you when it comes to things like hiring, promotions, and admissions. If you really DO belong to that ethnicity, it's time to admit that, as a member of that ethnicity, you are subject to discrimination.