Why is genocide a real thing

Because people are sinful and do this to people.

Genocide has occurred several times in our contemporary era. These are examples of genocide since the 20th century: the Armenian genocide at the hands of Turks in 1915; the Holocaust of the Jewish people during WWII; the Rwanda genocide in 1994; genocide cases during the last war in the Balkans in the 1990s. In recent years, the systematic persecution, killing and ethnic cleansing of the Rohingya Muslim people in Myanmar has been called by many human rights activists "a genocide."