Also, we know that some of those pre-human species interbed and co-mingled with each other. The dynamics between tribes is also completely different from modern racism.
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.
With respect, it can be hard to see the nuance in this if you're from the US (a country that is so racist even the government openly practices it, but sanctimonious enough to pretend it is instead free).
