In summary it is down to the fact of the features of colourism in India manifesting in the American setting, and then creeping into Africa.
Let us consider the nature of colourism in three different parts of the world, Europe, Africa and Asia. In Asia. In the case of Africa I am referring to Sub-Saharan Africa and with Asia I am referring to Indian subcontinent in particular.
I focus on these three regions in particular on account of ther racial and ethnic homogeneity, although in India an allowance has to be made for caste differences.