It's not over atomic energy. It's that it's no coincidence that all 5 members of the UN security council have nuclear weapons. The threat of their use gets things done, and that fades the more countries have nuclear weapons. So, insofar as there is a sinister motive to Hiroshima drumbeating, it's specifically to preserve the viability of the nuclear threat. Consider how different the current war in Ukraine would look if Ukraine still had nuclear weapons. How different would the situation in Gaza look if any of Israel's immediate neighbors also had nuclear weapons?

I'd also argue that the correct emotional response to the destruction rendered by a single airplane (vs. the 325 used for the Tokyo Firebombing) is abject horror, and that should cause any person to seriously question their use.

I'm not here to dispute that nuclear power is good or that the alternative to bombing Hiroshima and/or Nagasaki was worse than the bombings. It's that while Truman et al may have understood the extrema situation the Allies were in, that's no guarantee that future users of atomic weapons would be so deliberate.