Added additional context to your question:

> Say as an armed soldier, you're about to be shipped out to run up a hill and killed by Japanese machine guns.

> Wouldn't you prefer Truman use a super weapon on civilians to end the war ?

I know WWII blurred the lines on what counts a legitimate target (military installations, civilian-manned factories, entire towns like the firebombing of Dresden). As a soldier, would you be able to justify indiscriminate targeting of unarmed civilians? I suspect some Americans lack empathy on that part because the US homeland has never had a hot war in a very long time to the extent that is not imaginable.