Race is a social construct (meaning there is no scientifically supported biological evidence and the only people that support that there is are in fact racist themselves) designed to divide ethnicities into a hierarchy with White consistently being at the top and Black consistently at the bottom, to acknowledge oneself as a "white person" one must ignore your original ethnicity. Or shuffle back and forth depending on the occasion. "White people" have also consistently been in charge of deciding who stands where within this hierarchy (based mostly on skin color and hair texture...did you know North Africans and people of middle eastern descent are categorized as white racially) and have maintained political, social, and economic power. The British empire didn't really end, did it? Well, not from the view of a Person of Color.
People of Color, a term itself that only exists due to "White" implying homogeneity regarding the "others". Just like how back in the day "Chinese" was considered an entire race.