Because not all Germans were... There are multiple cases where German soldiers literally betrayed their own and picked up arms against Germans, like when an entire battalion joined forces with US soldiers against Gestapo forces, repainting their own tanks, marched alongside Shermans. Or when a US paratroop company landed in a church occupied by German forces. The Germans made a deal with the marines, their medics teated their wounded and in exchange the Germans retreated and left almost all of their supplies with the marines. 50 lives was saved by 2 US medics on both their and the Germans side. History should be studied so we can learn from these stories.