Think about it like this: What do you do if everyone is at least complicit? While the soviets excluded the old elites from their new regime, the west focused more on reintegrating them. That being said, both sides were willing to turn a blind eye if you where qualified enough and needed for the continued function of society.

So for example the head of the neurological society was a doctor who experimented on brains of executed prisoners and children. And unfortunately this was the rule, not the exception.