The only reason such a rationalization was ever brought forward is because they were brought to face judgement by a group of powers seeking to enact some form of justice for the atrocities committed.
IOW, “just following orders” will never be a defense offered if there’s nobody to put them on trial.
It’s a huge assumption that there will be anyone to put those kind of people on trial in the US and dispense any meaningful justice at this point. Current dems won’t do anything. Current judges can’t seem to pass sentences that stick.