[TomGuy]

Then, there are the babies who grew into the right-hand henchmen. Should they have been killed before they turned into the Dr. Mengeles and Goebbels, etc.?

[drpix]

You bring up Dr Mengeles. Have you seen the movie "The Boys from Brazil?"

The main villain is a Mengeles like fugitive Nazi doctor in South America secretly cloning a bunch of Hitlers. Great actors and excellent story made for a very good movie,

If you didn't, here's a youtube full version: LINK