It's just not smart to piss them off or arouse them, volunteers would increase for the army and opposition to the war, such that it is, would be harder. That's aside from it being a war crime and we are trying to enforce international law. It's easy and natural to be pissed about this shit, but anger while useful for motivation is poor for planning and execution, despite the movies. Vlad does shit for emotional reasons, like being pissed his bridge got blown up on his birthday and wasting diminishing ammo over it. This shit won't help him where it counts, on the battlefield and it won't keep his army from collapsing either.