It's true...not every nazi died in WWII. And some of them were highly educated and skilled so their expertise was put to use after the war.
Many German scientists and von Braun in particular were whisked away from Germany and the Soviets at the end of WWII. 1,600 rocket scientists were shipped to the US during Operation Paperclip. It was a coup for the US (and the Allies) and a loss for the Soviets who also wanted them.
However, the Soviets got their fair share and that is how their rocket programs developed so quickly as well.
To pretend that this somehow means that the nazis won WWII is utter nonsense. We simply didn't murder all nazis after the nazi Reich was THOROUGHLY defeated.