From your own wording, even you don't quite believe that propaganda.

Esp since both nukes and fire bombings did far more damage to civilians structures at that point.

Even if you ignore the wanton destruction, Russia flipping over to allies and cornering Japan by that time would have been enough to destroy Japanese moral as much as the fire bombings did.

So really the excess use of force by that time wasn't really needed, and trying to justify it now sounds like making poor excuses at revisionism.