There is a lot of truth to that. There is a reason that Hiroshima and Nagasaki were the targets for nuclear attack rather than larger and more important cities such as Tokyo. Those larger, more important cities were already largely destroyed by fire bombings. It would have been a waste of the A-bombs to use them on targets that were already largely in ruins.
The A-bombs certainly caused mass casualties, but what do these people think would have happened in Japan had the war dragged on for another year or more and an invasion of the home islands occurred? More fire bombings and massacres of civilians would have been the likely result.
these revisionists are acting like there was nothing going on in the world at that time...like the bombing was all done on a lark. Again, 60 MILLION had already died. Phillip Morrison, physicist who worked at Los Alamos, said they would turn on the BBC everyday...not to listen to the news, but to make sure London still existed. Hitler was sending V2 rockets there....nobody knew for sure what anybody had.