I have a student who has a very Hispanic last name. If he added an accent mark to his first name (his middle name is already acceptable), he'd be about as Hispanic as one could get.
He's also about as white as one could be. And I don't just mean in skin color.
The discussion lately is: can he legitimately mark "Hispanic" on his college applications?
If you say no, then what about him is not "authentic" enough for you? What about my best friend from West Point, whose father was German (naturalized American after WWII) and whose mother was Mexican, who lived just across the border in Mexico but attended American schools each day, who speaks fluent Spanish--but has blond hair and blue eyes? Is there a skin darkness that determines who is, and who is not, Hispanic? If not, then what defines "Hispanic" beyond a Spanish-sounding name?
And what about my blond Venezuelan student? He, too, is fluent in Spanish--I'm quite sure that at least his father speaks English as a second language--and visited family in Venezuela earlier this school year.
What about the darker skinned Hispanic students I've had, whose only "ethnic" quality, by their own admission, is their last name?
When real-world situations like this arise, the absolute folly of considering race is arrayed in full view.