Nonsense. Despite his hard left politics, Studs Terkel is one of the best interviewers alive. He lets the other fellow talk, rather than argue with him or pass judgment. This was first-rate work.
Why is Studs so surprised by this. We've always known it, if we were paying attention.
The bomb was being developed to use. And to end the war when it was used. All planning assumed it would be used first in Europe, because the strategy was unvaryingly: Germany First.
By the early Spring of 1945, it became apparent that the bomb wouldn't be needed in Europe -- Germany was beaten. Accordingly, attention was then turned solely to Japan.
We know from Richard Rhodes' "The Making of the Atomic Bomb" that several of the physicists involved in the project resisted the bomb's use on Japan. As Jews and European refugees, they had been motivated to develop the bomb so it could be used on Hitler's Germany. They had no wish to unleash havoc on a country against whom they held no personal animus.
Of course, the bomb would've been used in Europe. If that's what it took...