The Importance of Race in Social Equilibrium

When I was a kid, I grew up in a very predominantly Hispanic group. But the Mexican American community called some Blanco's and Blancos. They meant people from Mexico not intermarried at that point. Most of them married somebody either that was not in their particular ethnic group. Can't they decide what they are? Do they have to always be constructed as Latino? Maybe they don't feel Latino. And then on the other hand, I won't mention her name because she still may be alive.