I didn’t put those words in your mouth - I drew the contrast with “collective responsibility” in the sentence right after I mentioned collective punishment. I even put it in quotes and didn’t for collective punishment.
Also, while we’re laser-focused on 20th century Germany, we might as well look at it just before WWII. The Treaty of Versailles (in addition to being practically punitive) had a clause that is commonly referred to as the “War Guilt Clause” that justified their onerous treatment after the war, and the Weimar Republic had public debate of what they called the Kriegsschuldfrage (literally War Guilt Question) before the Nazis even came on the scene.
I don’t know if the literal term “collective responsibility” was first used later, but I don’t see how the concept is so different. Sure, the Allies did a better job of driving the concept into public consciousness the second time around via prolonged occupation - but they clearly felt justified in holding the German people responsible the first time.
