> based on someone’s skin colour you are determining their culture/heritage. What does a Nigerian have in common with a Jamaican, apart from the melatonin in their skin?
Based on their skin color, they are treated the same way by much of society. They are often compelled, for safety and for just day-to-day peace from racism, to live in the same neighborhoods, go to the same schools, eat at the same restaurants, visit the same websites (where they don't have to read racist comments), play the same online games (ditto), etc. - heck, you can't even watch porn without encountering endless racist portrayals based on skin color. So people with 'black' skin have many common experiences.
Also, market segments don't have to be perfectly defined. We can always find flaws - no two people are alike; no one person is exactly alike from one day to the next.
Based on their skin color, they are treated the same way by much of society. They are often compelled, for safety and for just day-to-day peace from racism, to live in the same neighborhoods, go to the same schools, eat at the same restaurants, visit the same websites (where they don't have to read racist comments), play the same online games (ditto), etc. - heck, you can't even watch porn without encountering endless racist portrayals based on skin color. So people with 'black' skin have many common experiences.
Also, market segments don't have to be perfectly defined. We can always find flaws - no two people are alike; no one person is exactly alike from one day to the next.