Then he came to the USA, and played the same con on Congress to fund his continued work here.
So in your view von Braun was an amoral, self-agrandizing liar who was willing to actively engage in the selection of slave labour working in death camps to build rockets that killed thousands of strangers just so he could play with cool toys? Because that's what you're describing.
I say "self-agrandizing" because everything that von Braun wanted to do would have been done without him, without the 12000 dead slave labourers, without the 9000 dead British civilians.
I've had some pretty extreme scientific and technical ambitions in my time, but have somehow been able to realize many of them without killing people, and have given up the rest because: killing people. So I'm willing to pass judgment on von Braun in this respect: if he faced a choice between following his dreams and not killing people I'd have to say the latter is the far better choice.