I think you need to read up on some the cluster analysis work that has been done over the last decade. Your statement about inventing races and assigning them to people isn't true.

I linked this in another comment but ill mention it again, this article makes a comprehensive argument for race while linking off to the supporting papers instead of just me shotgunning a bunch of papers at you.

http://thealternativehypothesis.org/index.php/2016/04/15/329...

Look under the heading "Genetic Clusteredness" and you find a summary of papers such as Bamshad 2003 which explain how they can conclude a strong correlation between self reported races and objective measured genetics via SNPs.