The Hutus tried to kill the Tutsis, because the Tutsis helped the white people during colonization, they are also two different ethnic groups, Hutu's are short and dark, Tutsi's are tall and light-skinned.
The Rwandan genocide is also one of the times that the UN peacekeepers showed that they were useless, they literally cannot keep the peace under law, they can only attack if they themselves are attacked, so they have to watch a group of civilians get hacked to death with machetes and cannot intervene.
