Promising a deal that includes citizenship, a house, a salary, and an administrative position to a Nazi scientist in exchange for their work and knowledge such that one's country can gain ground in a cold war is absolutely fine. It's absolutely totally fine.
Following through with the deal after getting the goods from the Nazi is not. Shoot the Nazi. You always shoot the Nazi.
Ah, now I will admit to there having been a potential nuance. I certainly would want a trial before an execution, for instance. But I also think it would be wrong to assume these scientists were completely morally innocent. Maybe I could be persuaded from my earlier opinion of "You always shoot a Nazi" but there needs to be something to show. A diary entry saying "I'm not sure about this Hitler fella." Something.
What you're suggesting is stooping to the level of the nazi cruelty by a complete breach of agreement even after the other party has fulfilled their terms. Also what was that pathetic attempt at baiting the other guy by saying: "aRe yOu SuGgEsTiNg iT iS wRoNg tO sHoOt NaZiS?!!". Like that wasn't even the point of the other guy.
I think many of the scientists weren't Nazis, but rather forced to work for the Nazis, fearing for their and their family's lives. I could be wrong though, it has been a while since I've investigated that matter.
To be frank, it would be hard to siphon out truth from fiction at this point from personal accounts. That said, of course I distinguish between a forced Nazi accomplice and a sympathizer. I am not suggesting that they should be treated the same. I am suggesting that the U.S. was so zealous in its efforts to defeat the Russians that it wasn't making distinctions.
The second one makes for one less Nazi. Thus less warcrimes. Dont tell me theres some magical "cycle of hate" you're beholden to, just for putting down a child-killing government operative.