I can see your point, and I'll concede that it was not necessarily a foregone conclusion that he'd have become a monster regardless of environment. I guess I was mostly thinking that had he actually gone on to do things like that outside the bounds of WWII, he'd have been (rightly) labelled a serial killer, but you're right in that perhaps the circumstances of his role in WWII induced his transformation into what he became.
If you've got some time, in case you haven't seen or read up on this before, you may find it interesting to check out
the Stanford Prison Experiment, which for the most part reinforces your point, IMHO. They took a bunch of mostly ordinary individuals, and had some play the role of prisoners, and some play the role of (largely unsupervised) guards. It had to be shut down after only six days, due to how detached and sadistic the 'guards' had become.
So I suppose you're right that it is difficult to say if Mengele would have become that sick and twisted had it not been for the environment in which he was operating. Regardless though, I don't have any problem abhoring him and his actions - I personally believe that moral subjectivity does not extend to the levels at which he violated human decency. I'd like to hope that 'most' people would not accept a similar presented opportunity, but that's probably sadly questionable as well, depending on the circumstances (for example, see the
Milgram Experiment). Some very scary stuff came out of those tests regarding human nature in extreme conditions.
Apologies for the slight hijack there,
Meleager.