Nearly all animal and bird species and even fish are territorial, some are territorial in groups, animals like humans and apes are, its part of the way we evolved .
You have extended family groups they compete with other extended family groups we call tribes, this competition is deadly, and you have altruism but its normally limited to your kin .
So to a degree racism is a part of nature and evolution, normally the tribe whose members put other tribes interests first is doomed.
I think this is a hurdle that any anti racist comes up against humans are naturally tribal they operate better in more monocultures they are more likely to have better run societys.
" More ethnically homogeneous nations are better able to build public goods, are more democratic, less corrupt, have higher productivity and less inequality, are more trusting and care more for the disadvantaged, develop social and economic capital faster, have lower crime rates, are more resistant to external shocks, and are better global citizens, for example by giving more foreign aid. Moreover, they are less prone to civil war, the greatest source of violent death in the twentieth century.."
personally I'm pretty sure america will break up ethnically much in the way of the book civil war 2 by thomas chittum. When that happens I'm also sure most of the people now banging the drum for multi-ethnic multi-cultural states will be saying well we knew it would come to this all the signs were there .