Beyond sickness...that is Satanic.
I think that it is important enough to mention the Hutu and Tutsi violence was not tribal. It was more about class.
In fact, the two originated many years ago as class.. "the people who owned the most cattle were called 'Tutsi' and everyone else was called 'Hutu'" quoting a wiki source. I remember from the book that colonialists considered the Tutsi more European-like, such as lighter skin and a taller build and ID cards were required to list Tutsi or Hutu.
They lived and worked together, intermarried, and the only way in many cases that one was distinguished from the other was the ID cards. The husband's ID usually applied to the children. You could change the designation also.
IIRC there was longstanding enmity between extremists on both sides -- the origin of the genocide was political and started from comments on a popular radio show. Eventually the phrase "Cut the tall trees" caught on and spread. The machetes were handed out by the thousands to the Hutus.