Being director of a space flight center puts him in charge. He may have some higher ups, but not many. He should have faced trial for being in th SS. Instead he got a promotion here in the States. If you see nothing wrong with this I feel sorry for you.
In charge of one of the many individual units that comprised NASA at that time does not mean he's running the whole shebang,
which is what you claimed. Don't try and weasel out of it.
Von Braun felt he had no option but to join the SS for the benefit of his work, which he would not have been allowed to continue with otherwise, since the SS wanted to take charge of it. He was in fact arrested by the Gestapo and held for two weeks in 1944 and only released when one of his close colleagues argued on his behalf that he was an asset to the V2 programme. There is significant evidence that he merely followed the safest path for himself in a heirarchy that did not tolerate the slightest dissent. One of his colleagues has been quoted as saying that if he had spoken out against the use of slave labour or any of the other atrocious Nazi working practices, there is no doubt he would have been shot.
It's fairly clear that Von Braun found the Nazi ethic fairly distasteful but felt powerless to do much about it. As I said before, do your sodding homework, Hoppy.