You have absolutely know clue as to what you are spewing. The only part of "history" that says it wasn't necessary is the part written by a bunch of far left, commie "intellectuals". I suggest you read Downfall : The End of the Imperial Japanese Empire before opening your mouth again.
It's "no". I trust people like Eisenhower, Leahy, and MacArthur over that of Truman. You seem to be quite upset about this for some reason. As far as communists go, there were certainly enough of them who had infiltrated the American government at the time.