If there were no European intervention, these people would still be butchering each other without the world knowing about. They probably were butchering each other long before the Europeans arrived. Hell they butcher each other on a daily basis without any white man's involvement. I mean, no white man told Mandela's wife to put tires around people and set them on fire.
No outsiders involved when they hunt and kill toddlers as witches
... or when they cut off limbs of albino children
It's a messed up, dark continent