I don't believe those are good arguments though. "They committed war crimes so X is justifiable". That's part of history, being able to learn from past actions. The supreme allied commander said, at the time of the bombing, that it was unnecessary. I don't think anyone would accuse Eisenhower of wanting to lose American lives, or not being in a position to criticize the decision The bomb or invasion is a false dichotomy.
And would you then argue that having seen the destruction caused by the bomb contributed nothing to stabilizing the framework of MAD, with the emphasis on Assured Destruction?