Sports. Watch the crowds in some European soccer or basketball matches and you'll see how we managed to keep tribalism alive and well, but (mostly) harmless.

(You need stadiums that can handle tens of thousands of people bouncing on the stands for ninety minutes without collapsing, though.)

In reality, it's not purely about race. Most racism isn't between groups that are culturally identical, it is between groups with significant cultural differences. Race is just the most obvious attribute used to identify the other group.