It’s not that there is no such thing as race. There are measurable genetic differences between, say, a “white” and a “black” person. It’s just that race is not so specif-c ordefinable a category as we pretend, and certainly there’s no such thing as racial purity. I don’t even know what that’s supposed to mean, really. But you fall over backwards in the other direction when you deny race altogether.
What race is, is simply adaptation by humans to different climates and food sources. That’s it. Of course there’s mental and physical differences between ethnic groups. No denying that. But when many people think of race, they think of separate species of humans. There is no separate species.