I don't believe this mindset is correct, and I'm sure you don't either. Therefore, I applaud the movie for its underlying message. But, I think critics may have been a bit too harsh in attacking this movie. I can't remember the exact wording, but that was the gist. I think it is illogical to state that atrocities such as the ones portrayed in the film were never committed.
War is a savage and bloody thing, and it can drive men out of their minds.
I'm sure that atrocities were committed on both sides, but this being an American movie, the American atrocities were whitewashed a bit. The villain was made more evil so that the cause would seem more just. This is the nature of all stories. The fact is that none of us can say what really happened, so we should really not criticize those who choose to speculate. I suggest that if any of us have an idea of the content of history, we should go make a movie.