[Houshalter]

That's not really true. If you look at just the basic PCA of genetic data, several races emerge very clearly and distinctly. E.g. look at this image: https://i.imgur.com/J2Xl2FK.png

I'm just guessing here, but I think the problem is they are trying to do something more complicated than just find your nearest genetic cluster. They want to find exactly what mix you are between different clusters. It's clear on the graph that some people have more African ancestry than others. But what would be an algorithm for working out the exact percentage "African" someone is? Is it euclidean distance to the median african? Or the furthest bottom left african? Or is it just the first principle component alone?

The second problem is they don't just want 7 big clusters. People already know they are European, they are more interested in exactly what countries/regions they are from. And making a bunch more clusters makes the problem more complicated.