But they do. People from areas where high melanin content is the norm still burn and tan in the sun and fade away from it. Noticing that a particular person has a tan (or has skin that has darkened in exposure to the sun in a way that for which the ethnocentric word in our language happens to be based on a change to a specific color), is the epitome of seeing the individual and not the group. it is not true that only Europeans and their descendants have skin that changes color as the result of changes in sunlight exposure; it is only true that people who are more used to seeing the changes manifested in people like themselves will not notice such changes when manifested among other people with whom they are less familiar. (It is possible that the changes displayed on European-descended people cover a wider arc of the color spectrum, but all groups change color based on sun exposure.)
I’m not at all sure what you are objecting to in Zoe’s post.