How many said "Sorry Joe, I am not interested"?More than 4,5 million Ukrainians fought (for several reasons ) for Stalin,less than 450000 fought for Hitler .
Heydrich said that the Germans were welcomed as liberators in the former Polish Ukrainian territories, but not in Soviet Ukraine .
That's the main reason why Stalin occupied Eastern Poland ,which was dominated by the anti Polish and anti Soviet OUN.
Source : Collaboration in German occupied Ukraine .