They can still be blackmailed.
Anyone can be blackmailed. What Mr. Apology seems not to understand is that given the culture at that time blackmail potential was great enough that there rules of that time maybe made sense. Instead he foolishly is trying to pretend that the past was different and the agency was wrong.
I guess leftists successfully managed to get everyone to forget how much they like eugenics and national socialism so history is just a story to them now.