That is the point. They were trained up into an evil system and many of them did evil things, and they were endorsed. Vastly fewer American soldiers and marines did evil things. But some did, and they were often punished. My dad fought in the Pacific War and I grew up in a home that hated "the Japs." He told me of his real experiences. Sixty years later, it is not so terrible that these former enemies speak about equivalent "emotions" and glance over their actions. We are a just nation and most of our wars have been just. Still, we are prouder of some than others. I am glad that the Japanese are beginning to look at this at all.
The Japanese were not brought up in a Christian nation as our soldiers were. Even if the soldiers weren't all Christians, they were brought up with certain moral values and ideals. I believe that was the difference.