What does it say about the nature of racism? It says that humans are still more primitive animals than we like to believe. Dogs of different color size and shape get along and breed yet we can’t.
The fact of the matter is that the Tutsis and Hutus were arbitrarily divided by white Belgians based on things like facial characteristics. Before then the two tribes had learned to live in peace, and we’re pretty equal. Then white people came, gave one group the power, then left, and so the power structure remained.
I think it was racism. Either group thought they were better than the other, one group was more dominant politically and socially, the discrimination was based on a belief that the other group were inferior human beings (“cockraches” or whatever they said). But, all of this hatred between Tutsi and Hutu was a result of Belgian interference, pushing their race-based class system onto these peoples, dividing them and creating a class-divide that would harbor racist feelings.
React!