If we are talking about why most of the Nazis weren't put on trial the reason "they were in administration" is only half the truth as a lot of Nazis weren't put on trial because the US had a use for them or because they just didn't care enough. I mean look at how the Soviets approached denazification and how the US did. East Germany was a lot more thorough than west germany.
As an example SS members were allowed entry to Canada who had a very strict "no communists" immigration policy and their SS tattoos actually proved to be an advantage to prove that.