Ukraine's history with Naziism is very complicated. When the germans arrived, many Ukrainians saw them as liberating them from Russian occupation/aggression, and didn't mind or were ideologically aligned with Antisemitism. The Ukrainians had come out of a genocide committed against them by the Russians and so Naziism, as the primary anti-communist force in Europe, was aligned with Ukrainian nationalism. Whether you fought for or against the Nazis, you were joining the bad guys.