Older, less-informed biologists also gave us scientific racism.
Polar bears and Asiatic black bears live in different places and have different appearances and behaviors. They called those different species.
Norwegian humans and Chinese humans live in different places and have different appearances and behaviors. They called those different races.
If we're gonna go down that route, probably our genetics gave us racism. Many species are "racist" towards other populations that they might've otherwise bred with. Extant primates also engage in what would be called genocide if performed by humans. All just because the other group lived in some other place and might've looked/smelled/talked a bit different. Nature is cruel and unforgiving and does not give two damns about egalitarianism.
Equality is a human cultural construct, a social contract that attempts to minimize in-group violence. It is itself a cultural evolution, a relatively recent one in the West, longer-lived than that in other cultures, but altogether very limited and mostly only applied to some convenient in-group du jour, not humans around the world and certainly not to hominids at large.
Equality has no real evolutionary basis. Evolution depends on inequality in the face of selection pressures. May fit individuals breed, may adaptable populations persist, and may the sexiest genome win.
Scientific racism failed both because of changing social norms and because taxonomy-by-appearance was doomed to fail upon closer inspection, not because humans are inherently equal... we're anything but, and those "self-evident truths" are believed by no one in particular, not even grade school kids. It's ironic that the nation who says that on one hand has, on the other hand, produced one of the most unequal societies in human history.
If society is ever to actually become egalitarian, it must be because we -- by social contract or force of mythology -- place equal value on each individual, not because our genetics are the same. We're not clones and we're all better and worse at some things, and most of us are completely mediocre at everything except, maybe, being an adaptable hairless ape between ice ages in the temperate zones of a wet rock floating around a star.
In other words, we can't morphologically evolve our way out of racism, but perhaps -- someday, if we survive these next few decades -- we can culturally evolve more egalitarianism. Genomes aren't the only unit of information reproduction anymore. We can only hope culture will succeed where nature failed.
