Before there was race there were tribes. Which goes back to the very roots of humanity.
Just ascribing behavior we observe in humans to "human nature" is a thought-terminating cliché and prevents looking deeper into how we got here and why. Modern society didn't pop into existence fully baked and that goes as much for the good (which we rightly laud as important achievements we need to preserve) as it does for the bad (which we often just describe as "human nature" to avoid challenging our assumptions).
If everything bad is human nature, there's literally no way to improve things. If everything bad is human nature but only for certain people, that's one step away from arguing that the only way to improve things is through genocide.