Race is real. It's the product of different isolated populations breeding, genetic drift, and physical adaptions to climates--usually hot ones or cold ones. Physical adaptions are passed down through generations.

For instance, many different groups of people living in equatorial areas have similar adaptions to the hot climate. Blacks, Australian Aborigines and Melaneisians all have dark skin and curly to kinky hair. Many Melanesians are physically indistinguishable from African Blacks. (I read a story about a guy from Africa who jumped ship in the Solomon Islands and lived there for years. The authorities determined he was a foreigner by listening to him speak. He looked like a native solomon Islander, and the natives are not Negroes.) The dark skin and kinky hair helps to protect the body from extreme heat.

Eskimos have developed shorter and thicker limbs than most other groups because that trait helps the body retain heat in cold climes. Lighter skin and hair helped Whites during the Ice Age to maximize the low levels of ultraviolet radiation and produce the vitamin E necessary for healthy skin.

Human beings aren't the only members of the animal kingdom subject to different physical adaptions among members of the same species. Grizzly bears are different from kodiak bears, asian lions are different from african lions, etc. Most of the finches on the Galapagos islands evolved from a common ancestor.

Race is a reality, but genetic populations are not static. They change, and the quickest cause of change is the influx of new genes from different populations (races.) For example, my kids are half White and half ethnic Malay, so a great deal of change occurred in a single generation. (And yes, they are the best looking boys in the world. It's one of the few things my wife and I can agree on.)

I agree that racial classifications are usually used destructively, but that isn't always the case. Law enforcement agencies need racial classifications to decribe suspects. Imagine if a criminal couldn't be described by race. Race is usually a readily definable aspect of appearance. It's much more efficient to use terms like White, Black, Asian, and Hispanic than it is to describe skin tone, eye shape, etc. America isn't going to be able to ditch racial terms anytime soon.