They were generally known as Hiwis (hilfswiliger) and German soldiers would call them 'Kokols' (tuftys) in reference to their haircut, used for all the dirty jobs on the Eastern Front. Caught between two weevils they hated Stalin more after the Famine induced at the beginning of the 30s. Ukranians called those times The Holdomor and still haven't forgotten how they suffered under the Communists. Putin's admiration for Stalin simply strengthens their resolve to fight for independence.
*And the German Empire was experimenting on the people of Namibia in concentration camps before the First World War: proto-Fascist, you could say.