Because it's asking about ethnicity not geographic place of birth.
Honestly asking, not trying to nitpick.
>White. A person having origins in any of the original peoples of Europe, the Middle East, or North Africa. It includes people who indicate their race as "White" or report entries such as Irish, German, Italian, Lebanese, Arab, Moroccan, or Caucasian.
https://www.census.gov/quickfacts/fact/note/US/RHI625219#:~:....