The Roma were just one of the ethnic and social groups the Nazis decided should be annihilated. The Croatians (Catholic) attempted to eliminate not just the gypsies but the ethnic Serbs. I've stood at the site in a little Serb village in present-day Croatia where the Ustase (Nazi-supporting Croatians) machine-gunned women, children, the elderly, every Serb they could round up - dozens of them - on Orthodox Christmas. I thought it was strange that so many Catholics were killed by Nazis at Dachau, yet the Catholic Croatians still joined up with them.