Interesting contrasting views.
I would submit that a person should simultaneously be capable of killing if necessary during war and also making sound judgments in other areas, thus it's perfectly acceptable to criticize the soldiers for this regardless of the fact that they would have just killed those same now-dead bodies.
Given what we know about the power of propaganda, and what happens to certain segments of the Muslim extremist population when, e.g., someone draws a cartoon about Mohammad, it's not unreasonable to expect our fighting forces to realize how incendiary something like this could be. This isn't fog-of-war, heat-of-battle stuff, this is people whipping out dicks and a camera and cracking wise about it.
Yes, the dudes were already killed, and yes, plenty of Middle Easterners hate the U.S. plenty based on that already, but this is throwing fuel on the fire.