In contrast to the ongoing tribal warfare in Africa, the Dinka and Nuer get along in America. We sometimes try to force the African warfare into a Muslim-Christian narrative, but that is only partly true. The tribal warfare, especially between the two major tribes, dominates the landscape. Serbs, Croats, Kosovars all get along in America That is not 100% true of all conflicts, as there are still animosities that get carried across the many waters of the world to here. But the tendency is strong. (Canada too, I should mention. I try to remember not to leave them out just because they are a smaller population when they are one of the voices of sanity.)
The mere moving to another land may be the great part of the ceasing of hostilities. However, I think the American experience is also part of this.