And where do you place the deaths of 15 million Europeans in the Nazi death camps?
Or the deliberate starvation of 6 million Ukrainians?
Or the substantially greater loss of life in the firestorm at Dresden?
Or the untold deaths in the Cultural Revolution?
Or the Rwandan genocide?
Or the massacres in the Tai Ping rebellion?
Or the massacres of Tamerlane?
Or the St. Bartholomew's  Day massacre? 

The use of atomic weapons against Japan will always be the subject of controversy.  It is, however, indisputable that those bombings did, finally, end the Asia-Pacific portion of the most calamitous war in human history.

Whether or not you agree with Truman's decision, it is undeniable that those actions had a clear and rationally defensible purpose.