Nobody but a moron would argue that atrocities were not committed by the Allies as well as the Germans. The difference being that acts committed by the Allies were random and many of those committed by the Germans came down the chain of command, " I vass only following orders."
Not so random, from what I've heard. According to the fellow I knew, executing German soldiers, often cruelly, was not uncommon at all, though certainly the circumstances of their capture mattered. If they resisted and killed allied soldiers, then tried to surrender, it was more likely their surrender wouldn't be accepted. Whether they were executed, and how cruelly, all depended on how willing the officers were to turn a blind eye. This was a fellow who simply didn't believe in treating anyone inhumanely. He seemed to feel that he was doing his job, and the Germans soldiers were just doing theirs. He actually told me about a couple of the German POWs he met that spoke English, and he was able to converse with. One was an older man, and he was quite intrigued with why such an old man would be fighting. Their stories were pretty interesting, but I won't recount them here.
Later his unit was pinned down in a cementary by an MG 42 team, taking cover behind head stones. He was hit in the head by a bullet that first broke through the edge of the headstone he was behind. He ended up with a steel plate where his skull was shattered.
Actually, I've been pretty fortunate to meet some very interesting veterans in my time. Several decades ago, I even met a real old timer, 112 years old. He was telling me about his wartime experience fighting, and I thought he was referring to WWI at first. Turned out he was in the Boer War. He was underaged, and serving as a flag bearer.