Slavery was normal throughout most of human history. War, murder and rape are natural parts of human behavior. That doesn't mean those things are good. Civilization occurs when we tame our nature, control our worst impulses and embrace reason and evidence.
I'm not saying a certain amount of tribalism is not acceptable. I like people who are similar to me. I like the culture and values that I grew up in. I don't want government funded mass immigration, because I want to preserve these things. But it is one thing to want to preserve that which you hold dear, and another to see others as worthless or lower than you. We cannot lift ourselves up by denigrating others. Ethics must come before tribalism, the virtue of a person's character must be more important than the color of their skin. Otherwise, we give in to our darkest impulses, no better than cavemen.