People would continue to focus on other differences they feel make them more superior than others. The human ego deplores equality.
Someone always has to be the best or worst: #1 or last.
If everyone on the planet were white there would be debates over whether or not those with blue eyes were more intelligent than those with green or brown eyes: Blondes VS Brunettes: Tall VS Short...etc
Human beings would find a way to "group themselves" differently.