No, sorry, you’re just wrong here. You can run PCA with pretty much any set of genetic samples and get a very nicely clustered graph, because that’s what PCA is for. See this PCA graph [0] on population groups present in Brazil. Should Xavante people be the sixth race in your taxonomy? They sure look distinct from other Amerindians and very distinct from the rest of the world!

(No, of course they shouldn’t. It’s just that extracting features to artificially cluster points along the most characteristic axes is what PCA is for.)

[0]: https://commons.wikimedia.org/wiki/File:3D_PCA_plot_of_Xavan...