Possibly something to consider as well is that a) under virtually no circumstance would these people ever have to face trial, because rocket scientists are a valuable commodity, and b) the US/USSR were already nudging themselves into the Cold War before the Germans surrendered. If the USA didn't nab these scientists, the USSR certainly would have. I see it was mentioned in the reddit post you linked as well. Another thing to consider, is it would be much easier for the US to keep tabs on these people if they were brought to the US and employed in government jobs than if they went to the USSR, or Argentina like many other Nazi officials.