As an outsider, it's obvious looking in that racial classification in the US is just crazy -- they took some racial stereotypes from 100 years ago, gave them neutral sounding names, and started pretending it's not racist to group everybody south of Texas as "hispanic". And then build official policy on top of these simplistic classes that fail to describe reality in any meaningful way, only serving to reveal to everybody else in the world what the people in the US think about them.
At least the people calling anybody with slanted eyes "Chinese" and anybody that's slightly brown "Mexican" are being sincere in their ignorance.
