Considering what the Nazis did, there is PLENTY of blame to assign to them. Not all Nazis were monsters of the Concentration Camps, nor were they all SS people. The average German solider was just that, a soldier doing his duty as he saw it, and joined the Nazi party, if he did, so he and his family could get food. By 1943, if you were NOT in the party, you didn't get food or other rations.
After years of war, and casualties that were caused by the war, yes, the Allies attacked anything that moved until the war stopped and there was an official surrender. I tend to believe the root cause of the war was the Treaty of Versailles and that, without it, Hitler would never have come to power. Regardless, the Allies were taking no chances on more casualties based on some hoped-for goodwill and a desire to end the war from retreating German troops. They still had ammunition and still used it when encounters happened.
Sure, there is always a story from the other side about how it really was, and many, if not most, are true. The average German didn't start the war, likely didn't WANT the war, and had no say in anything concerning the war. He or she was likely just trying to eat every day due to the poverty created by the Treaty of Versailles ... none of which stopped the war from beginning a few minutes early on 1 Sep 1939.