The original comment in question was referring to the genes that manifest in-group and out-group behaviors, such as the fear or general dislike for the "other". Considering a very large portion of the human genome is shared with most mammals, and most of it is shared with most primates, I think that it's a bit foolish to completely disregard genetic evidence from mammals, especially primates.
Most primate species are known to have rather sophisiticated social groups that manifest some of the social dynamics that we see in humans. As far as I know, specific fear for "unusual" or "odd" is an evolved psychological mechanism specific to humans, but it's possible that other primates have evolved similar psychological mechanisms.
Anyways, the point is that evolved behaviors involving hostility or aggression towards others who belong to a different social group are not unique to humans and exist in other animals.
Now this is a well written post, with actual points, but see my comment above about chimps vs bonobos. Also I could make a variety of other interpretations of the science sounding word applesauce that jsquared wrote
And, you post also doesn't explain why racists think of other races as "other". Is it just that they haven't been around enough people of different races? Evidence is that is the case, so the point of some sort of evolved racism that you sort of imply is imho not solid
Jsquared, if you want advice on how to not write posts as worthless as yours are, look at Eli's here.