Slavs sent 1000s of Slavs to the gas chambers.
Croats massacaring Serbs to be more precise (If a little over simplistic)
Also by the closing days of the war the Waffen SS was choked with Slavs, Croats and Ukranians in particular.
I would agree with you though that given history any Pole or Serb (amongst some others) who is facist is also a bit of a retard