Yes it is, particularly if morally required as a civilized country (we don't accept the mass killing of civilians absent clear and compelling need), and if the mass killing would backfire in our faces and defeat our ultimate goal, which in this instance beyond the noble one of liberating the Iraqi people, is to pacify the Muslim jihadists. Your policy would breed more of them by the hundreds of millions.
Disagree. Being humane will save American lives in the long run. That's why our soldiers (of which I am one) don't fire on crowds when they recieve fire from them. The long-term implications (risk of mission failure) of civilian casualties are considered (by the guys on the ground making those decisions) to be more important than the risks of the fire they take.