Well, although it seems really crazy and stupid to us, to them, it makes perfect sense. If you want the world to be a better place, and a certain group is screwing it all up, you destroy that certain group.
Hey, Shad? You familiar with the Armenian genocide? The Turks raided the land of Armenia and deported or killed thousands upon thousands of Armenians. I know this because my former Latin teacher, Dr. Chakemian, is the child of two Armenian immigrants, forced to move to America because they got deported. He was so sad that he didn't learn to read and write Armenian from his mother before she died...