Glad you forgot about the War of Northern Aggression.
Tell me about a situation during the WBTS where one side talked the other into surrendering on terms, then slaughtered about 120 men, women and children without mercy.
If you can give such an example, I'd be interested in seeing it. The greatest single atrocity committed on civilians during the War was the attack on Lawrence. During that, even drunk rebs treated the women of Lawrence with great respect, tipping their hats to them before tossing their wounded husbands into burning buildings.
During the Mormon Wars in MO, women and children were not murdered by either side. I know of no even vaguely similar incident in American history to the MMM.