A common refrain among non religious people is that religion is false, self contradictory, or something similar.
And yet the large overlap between these people and anti-racists cannot face the evidence that evolution applies to humans, and that genetic differences can have measurable effects. This becomes a core tenent of their (un)beliefs, that somehow we are all equal in construction, AND that evolution is real. Two completely incompatible beliefs (or concepts, if you can't stand such a word).
Prevalence of the MAOA gene is quite interesting indeed.
To expand upon that a bit, one deeply held belief is that Racism is wrong, not just morally but factually, that we are all exactly equal in nature. That our only differences come from nurture. The other belief (or "non-skeptically accepted prospect") is that humanity has evolved, first from africa, then in disparate populations spread over the entire land area of the earth, being subject to many varied natural environments and thus selections. Such natural selections MUST select for different traits, often wildly different. Such traits cannot be contained to "skin color only" a meaningless, arbitrary restriction.