We're getting pretty far from the original statement, but you've got some decent questions, so I'll go for it.

In your atheism example, you're correct. And the term racism is emotive; it's something that most people don't want to be even if the common definition describes their view. Assuming some races to be genetically inferior is what many would term racism. But what if it's true?

So, that brings me to the second part of your question. There are a lot of angles to look at this from, so I'll just pick the couple that are most important to me.

Let's start with history of dominant world civilizations. I'll pick an easy example: The Arab world. It was dominant intellectually, militarily and culturally in the European dark ages. Italian culture had fallen from dominance to backwardness in about the same time frame. If we're to assume that the critical factor was genetic, and that Europeans had a genetic change in that period that affected the whole of Europe, which in its rise had very little genetic cross-polination, you would need nigh-on miraculous perfection in genetic propagation for the whole of the population of Northern Europe to receive that gene in a couple hundred years. Simultaneously, you would need the whole of the Arab population to devolve.

If the thesis were that some families have a higher disposition to intelligence, that becomes very defensible. On the scale of populations of entire continents consisting of millions of individuals spread out over thousands of kilometers in largely distinct gene pools, it's virtually impossible.

You might be able to salvage an argument for there being just enough evolution in certain ruling families for it to tip the scales, but that's not very convincing to me, and doesn't leave you with the "differences between people" result either.

To be clear, I'm not saying that some ethnic groups may not have be genetically predisposed to certain physical or mental capabilities, but that those differences are not significant enough to explain the political tides of human history.

The less scientific part of my argument comes from experience. What are the most important factors in being successful in business? Drive? Connections? Understanding of markets? There are a lot of things, but most of them are en-cultured values. I've traveled through Africa, stayed with families, and met a lot of rather intelligent people. Many of them were still poor. The difference between me and them wasn't that they had The Dumb African Gene, but that I was born into a upper-middle-class family in the United States, and they were born into blue-collar families in Zimbabwe. My extended family also has some adopted members that are black. They most likely came from poor parents. They turned out about like the rest of us, went to the same colleges, grad schools, got good jobs and so on. Could they have had genetically weaker genes than the rest of us? Maybe, but that didn't seem to be terribly important to their level of societal integration.

It's pretty seductive to be able to think of the world's socio-economic problems in terms of genetic disposition; it makes us feel like our politics and policies don't play a decisive role and that our civilization is secured forever in its greatness. For me at least, history and experience do not concur.