This was common amongst the tribes of Africa. There would be war, and the victor would return with slaves and loot. But African slavery was much different from chattel slavery or the brand of slavery practiced in the Muslim world. When Europeans started trading with Africans, those slaves began to be sold much in the same way slaves were sold in other parts of the world in that time period. The allure of European goods was hard to ignore, but underneath the friendliness was cruel intentions. But not every tribe was keen to do business with the white man, and those tribes were usually eliminated and enslaved first.
What's neglected or forgotten is that once the demand for African slave labor reached a fevered pitch it was no longer a matter of going to the Chief/King and trading guns/liquor for slaves, now it was provoke wars between tribes and even between tribes and other Europeans who already had designs towards colonization. In the end, those African tribes you speak of that sold slaves ended up suffering the same fate more often that not. The drunk chief/king became a slave, the merchant became a slave, the shaman became a slave, the slave stayed a slave, everybody lost.
Europeans love to paint Africa as one big country. Its a huge fukking continent with 40 odd nations, that all have hundreds of different local tribes. Throwing all those people together is a smart way to divert attention away from what whites did to us for half a thousand years......on some "your own people gave you away" type shyt
They wasn't our people. One tribe enslaving another was no different than Romans enslaving Greeks. There wasn't any African identity. If you wasn't from the same tribe, you were an outsider. I used to have a major problem with it until I really reflected on it. Had the tribes we descended from had the upper hand, we would've done the same to them. It is what it is 
Respect. Breh, I'll be honest it's just as bad, if not worse, on the African end at times. (At least with Ethiopians, fools make me sick sometimes) To live in the middle of it is bullshyt cuz you can't relate with some family members and on the other end nikkaz say you ain't black even tho you fit the description, but we're the next generation after the older gen gets moreso imo it behooves both sides to come together. I was raised around nikkaz so I grew up around the AA experience(got AAs in my fam too) but it was a diverse group, Eritrean, Haitian, Ethiopian, AA, and yeah this shyt would come up and you'd hear the "Eri's/Ethi's ain't black" bullshyt but ultimately the cops treated us the same, cacs treated us the same, so in the end we was all black to them. This caste was made by cacs to begin with, so it goes as they go.
To me, yall are American Africans. Yall have been a part of the American Experience and built the country and have generations of roots here. But beyond America, yall roots lie in the motherland. Yall look like us, got soul like us, yall the American version of an African.
Yea bruh. I feel you. My eyes were opened coming to DC. It's way more diverse than anything back home. Being a PG dude, I'm sure you know that growing up here. There's Jamaicans, East Africans, Trinidadians, Nigerians & Haitians all over the city. Most of Philly is AA. Most of Delaware is AA. I was a little caught off guard
i didnt get this vibe of "animosity" on some tutsi shyt but they are divided even within the countries
and my other roomate still in town and we chat regularly 
if you sat at an african restaurant they would serve whites, asians, hispanics and jews before they even got to you
