In war, sometime soldier make mistakes, e.g. sometimes they get rice in their butt.
I'm sure that out of population of 100,000 or so soldiers you will get some soldiers who act in a manner which is criminal [and in environment where the other side is engaged in war crimes and/or in very stressful conditions and poorly commanded this can become even more common] and sometimes they even admit that they have commited war crimes & are not even prosecuted for this criminal behavior.
The more serious aspect of this is not if some low level soldier may have commited some war crime which may be hard to determine if due to accident [or because soldier became "freaked out"] or deliberate act of murder. It's far more significant when officers [who are suppose to have more training in this issue] are apparently deliberately commiting acts which are obviously immoral/war crimes. Not only is it "wrong" but destroys your troop morale and thereby helps the enemy.