I'll wager the grunts hunkering down in their bunkers at a firebase in Vietnam that was about to be swamped by hoards of attacking NVA weren’t overly concerned about the morality of the impending mass shredding when the arty gunners lowered their barrels and let rip at point blank with fleshette rounds... just had to remember to keep their heads down.
Take away the modern dumb conventional weapons like cluster munitions that help to give the ability to win a relatively quick and decisive victory on the battlefield and you run the risk of changing the way modern wars are fought, and it would probably be for the worse. It wasn't too many years ago when about the only way to defeat an enemy and their ability to wage war was to pretty much destroy their country, which caused massive civilian casualties. The negative aspects of cluster munitions, WP or any other modern conventional weapon used on the battlefield in modern conflicts pales in comparison.