I think the US command was still very aware of the lessons learned from WWII and particularly, those of how the Soviets defeated the Germans in Operation Barbarossa. The Soviet army might have pulled the triggers, but it was the Soviet people who ultimately won the battles and the war for them. They were resolute and could not be broken, even in facing the most daunting of environmental, emotional, and physical challenges. The Soviet army was largely a joke at the start of the war due to Stalin's purges of the military. They were soundly beaten time and time again by the Nazis. It was the sieges of Stalingrad and Leningrad where the people, ordinary citizens, made the difference. This bought the Soviets enough time to properly regroup, retrain, and rearm to end up fielding the largest, and later one of the most effective, armies of all time. If the people had given up or evacuated, the Soviet Union probably would have collapsed or been beaten back too far into Siberia to matter. The civilians were their ultimate weapon. I think the US command still remembered this when picking targets. You can shroud that however you want in terms of moral superiority -- a quick blow to the populace vs long years of sieges and urban warfare.

Aside: The excellent documentary "The World at War" is available on YouTube. Especially check out episodes 5, 9, and 11 to see how the Soviet people, not the army, beat the Nazis.