Does it matter?
There is good reason to believe that marines have committed such attrocities. Lots of people have said so. If they have done it, it would probably look very much like this scene.
It is the responsibility of the media to convey graphic images of those things that probably have happened. If it did not happen the public is equally served by seeing what it will look like when inevidably it does happen.
The public has a right to know what might happen.