Why, because America choose to divide itself based on race.
Its the easiest way to divide people because its easy I’m blue, Your red.
red people are bad, blue people are good.

tribalism is defining part of human society even we are are all the same colour we divide and conquer.
You don’t think “Racism/Bigotry” doesn’t exist in the rest of the world, There is no such thing as “African” or “Asian” or “Middle Eastern” those are term we created because we are lazy.

Japanese people hate none Japanese, they mass murdered South Korean because they are lesser race.
China has literally mass murdered everyone who isn’t Han, right now China has literal internment camp housing over a million people because they are not “Chinese” enough. China might be the most bigoted, Racist country in history.

Africa, Middle East, Europe its all the same.