My guess is that they were not only pretty impressed with the scientific (as well as "scientific") advances the Germans had made, but also found the Nazi's lack of moral qualms about things like mass murder, genocide, euthanasia, total political immersion and abandonment of the restraints of Judeo-Christian ethics appealing. And the OSS had its university communists, which is simply the international brand of socialism as opposed to the national flavor; the difference is merely in scope.
I also believe that rubbing shoulders with the Brits - whose elites have very casually and cruelly gaslighted their own population since before WWI in addition to ethnically and economically cleansing them since at least 1066 - also helped to make it easy to bring back to the US a slow but fatal form of ethical and cultural cancer.
A pox be upon them all.
As I like to say, "Not every German brought to the U.S. by Operation Paperclip got us to the moon."