There’s a bit of a difference between literally volunteering to fight for the nazi state and protecting von Braun so he could work for NASA.
Protecting von Braun doesn’t enable the holocaust and other Nazi atrocities. It’s machiavellian and realpolitik, sure, but the nazi atrocities are over by that point.
Literally enlisting in the SS, though, you’re either actively carrying out atrocities or enabling other people to carry out atrocities.