I feel like the 1 skin tone is meant to be provocative, possibly be a deliberate troll, maybe start a discussion.
does the author wish to weigh in?
as a white human I feel excluded. maybe I'm attaching too much importance to skin tone as a part of identity. I think partly that's in our brains, partly it's emphasised by the media to divide us and create outrage, for power and engagement.
OK, that's too short to really mean anything, so I'll elaborate. If you take the average characteristics of everyone in the world (wealth, skin tone, intelligence, BMI, height, gender, etc.), and turned that into a single person, then you would have a new, unique person. In other words, it would not "represent" anyone, and so should definitely be seen as controversial. There are a myriad of engineering stories about this discovery (one size doesn't fit all).
If anything, I would have loved to see more diversity, or at the very least a prominent message on how to achieve it. Color might be the easiest change to make, but I didn't see any old or fat people on there, or how to make those variations.
I like the overall idea of the project, though.