I'm not sure I can fully subscribe to your stated premise here. /u/kugelfang52 who is more of an expert on the post-WWII discourse of the Holocaust in the United States might have more to add on how this developed in the English-speaking world but for me, being a German speaker and having been taught and trained as a historian of the field in Austrian and German universities, it is quite the opposite from what you state.

What I mean is that both in public as well as academic discourse in Germany, the prevailing view in the 1950s and 1960s was that Nazi Germany was a "Betriebsunfall" (industrial accident) of history. The sentiment expressed in this term is that Hitler and the Nazi's rule in Germany was a phenomenon that had no direct connection with what came before, no continuity in German history. After all, so asked the purveyors of this view, how could the nation of Goethe and Schiller produce a genocidal mass murderer as its ruler? And so, for quite some time, historians – who had often been socialized in Nazi Germany – and politicians – who had started their career in Nazi Germany – took great care to exterritorialize the Nazis from history in general and from German history specifically. Ideas that anti-Semitism, imperialistic policies towards Eastern Europe, and the political use of mass violence were things that indeed had precedent and tradition within German history were dismissed and any hint at suggesting that it was not just Hitler and the Nazis but rather German society at large – the Germans – were also responsible for what occurred in the 12-year-rule of the Third Reich was labelled as "Kollektivschuldthese" (collective guilt thesis) and dismissed. The use of "Nazis" vs. "Germans" served in 1950s and 60s German the obvious purpose of drawing this distinction; a distinction so deeply entrenched in how this society tried to differentiate itself from its history that it even found entrance into how perpetrators were persecuted. People like the members of the Einsatzgruppen in the Ulm Einsatzgruppen Trial in 1959 and in almost every subsequent trial against Nazi German perpetrators were not persecuted for murder but rather for abetment of murder – Hitler, Himmler and the crowd sentenced at the IMT were the main perpetrators, so the judicial doctrine went, and all others weren't murderers in their own right but merely abetors. And so people like Hans-Joachim Böhme, who had in the course of being commander of an Einsatzkommando murdered thousands of people, were sentenced for the "communal abtement of 3074 murders" in 1959 rather than for murder itself and got off with 15 years in prison.

It was only over the course of subsequent decades that both this social view and the connected practice of writing exclusively of "Nazis" instead of "Germans" has changed. It took effectively until the 1980s for West Germany to embrace a different view on the past and started to institutionalize remembrance and make it a political point to speak of German responsibility for the past.

Naturally, these discussion over terminology have carried over into the academic field and the discussion of terminology with the greates importance is how the victims of the crimes committed by Nazi-Germany are discussed. Scholarship and popular discourse tends to discuss them as Jews but that is a definition that was forced upon through the Nuremberg Laws and similar discriminatory measures. In how they would define themselves, we know that many of the people persecuted as Jews did not perceive themselves as Jewish, primarily or at all. People like Viktor Klemperer, who did not practice the Jewish religion had not understood himself as Jew until he had been made one through official policy. Can we talk about Viktor Klemperer as a German? A German later persecuted as Jewish? Do we, in our description of the Holocaust, take over Nazi nomenclatura or do we make an effort to identify people like they did identify themselves? Should we talk about the people killed in the Holocaust as Jews and people persecuted as Jews? Or as gypsies?

In this debate I tend to favor the site of those who say that we as historians need to make an effort to make this differentiation to not too much transport the Nazi point of view or at least make it clear from which perspective we discuss the past. I'm not as stringent as I should be in the application of this in my writing, especially in this sub but the effort to talk about people persecuted as "gypsies" for example is worth the extra words and adds precision to historical analysis in my opinion.

When it comes to Nazis and Germans, the best arguments I have seen made, were about the usage in the service of historical precision. When we discuss for example the implementation of the Nuremberg Laws in 1935, it makes sense to talk about the Nazis because they were undeniable the political force responsible for these laws. But when we talk about discriminatory practice that resulted from said laws, it makes sense to talk of the Germans because the discriminatory practice that resulted from these laws would have been impossible, had not German society (as in those who were included in that project) gone along with over all. Similarly, when we talk of the crimes of the Wehrmacht in the Soviet Union, it makes sense to talk of the perpetrators as Germans rather than Nazi. Despite the fact that the Wehrmacht was a nazified institution, the people who committed these crimes were – in the words of Christopher Browning – ordinary Germans.

At the same time, the differentiation makes sense to keep even after 1938. E.g. the T4 program was a program initiated by the Nazis. But it was parts of German society who protested against that program and stopped it. And to make matters more complicated, the same people were often the same people who went on to shoot Jews later in the Soviet Union.

To me, it makes sense to make this differentiation clear where ever, one wants to apply it. There is a responsibility for the crimes that occurred to the Nazi leadership and there is a responsibility for these same crimes, we can assign to German society or the Germans as shorthand for that. These responsibilities often intersect but they are not the same necessarily. And historical analysis needs to make that differentiation to be able to precisely describe the historical process. It was ultimately Adolf Hitler who ordered the Jews of Europe to be murdered but the perpetrators of this program were often so-called ordinary Germans. The order might have come from up top but as the T4 program shows, it also needed German society to accept it and at least passively tolerate it. In that sense, when we talk about Nazis, we always talk about Germans but when we talk about Germans, we are not necessarily talking about Nazis. And where we use which term is imo up to the context.

Now, as for popular discourse, the rules are certainly more relaxed than in academic discourse and while I am certainly not offended by people talking about the Germans, I think in light of the issue of responsibility as well as in light of the discussion about how we talk about the victims, using Nazis and Germans not interchangeable but according to the context and what is to be expressed is also here the best way to go.

Thank you u/commiespaceinvader for drawing my attention here. And thank you u/gregbesia for the question. I would appreciate it if you offered some specifics on where you draw this idea (not because I disagree, but because I am always interested in sources).

First, I will consider the accounts written or testified to during the war when people (In this case I will be speaking of Americans) discussed the atrocities. Next, I will address what terms Americans used immediately following the war and why they used those terms.

The Liberation

The actual confrontation of Americans with the horrid nature of one aspect of the atrocities, namely the western concentration camps and work camps, led to an initial reaction that, combined with wartime antagonisms, suggests a general belief in collective responsibility of the German people for the crimes while at the same time portraying the Nazis as the perpetrators. By April of 1945, when the first functioning camps were discovered by troops of the Western Allies, the United States had been at war with Germany for close to two and a half years. During this time, the enemy was Germany. It was the German army and the SS both which Americans had fought in Africa, Sicily, Italy, and northern France. This means that Americans understood their war to be one against Germany. While this does not necessarily mean that Americans would view Germans as collectively responsible for the atrocities, it does mean that there had been the process of dehumanization of the enemy that occurs in every war. Thus, we must remember that the liberation of Ohrdruf, Buchenwald, and Dachau occurred in the midst of a devastating war.

By April of 1945, any semi-informed American had likely read or heard of accounts regarding not only the mistreatment of Jews, but of their extermination in camps in Poland. As early as 1933, descriptions of the mistreatment of Jews by the SA filled the newspapers in the United States. In November of 1938, the United States responded to Kristallnacht by recalling its ambassador to Germany—although not by increasing immigration quotas. Most notably, in December 1942, the Polish government-in-exile released a report which detailed the killings occurring in Poland in specific ways. It noted deportations, shootings, and gassings. It even mentioned the names of two extermination camps—Chelm(sic) and Belzec. Further, it accused Germans, not Nazis, of the crimes. For instance, its authors wrote, “the Germans have, in fact, transformed Poland into one vast center for murdering Jews.” The New York Times reported on this document in its December 20th edition. Notably, a subtitle states that the “Situation in Each Country Held by Germans is Analyzed in Summarized Form.” Later the author pointed to “German anti-Semitism” which had “grown until today the Germans intend to ‘wage this war until the Jews have been wiped off the face of the earth.’” Thus, when American soldier first set foot in concentration camps (not extermination camps), some of them, especially the most informed among them, had heard of some of the atrocities which had occurred and likely associated them with Germans in general rather than just Nazis.

The liberation of the concentration camps and the reports of it which Americans saw suggested a limited kind of collective responsibility of the German people for the atrocities found within the lager system. American troops first walked into Ohrdruf, a sub-camp of Buchenwald, on April 4, 1945 and they saw dead bodies everywhere (the prisoners had been marched to Buchenwald to avoid the Americans). On April 12th, and after Americans had also liberated Buchenwald, American generals Eisenhower, Bradley, Patton, and Lieutenant Colonel Creighton Abrams (Later commander of ARVN in during Vietnam) viewed the camps. Images of this visit were taken by the signal corps and other images of the camps were produced in such venues as Time magazine. One of the primary tropes in the accounts of liberation is that of the American, and British in Bergen-Belsen, soldiers forcing civilians, soldiers, and SS to view the camps or help in the disposal of the bodies. This suggests some kind of recognition on the part of the liberators of German collective responsibility.

Nevertheless, the statements found in these accounts provide insights which nuances this view. In a Time magazine article from April 30, 1945, the author describes citizens of Weimar (near Buchenwald) forced to view the atrocities. The article asked the question, “but how much of it was known to German civilians even in nearby Weimar?” The forced viewing and the statement that “A young Hitler Mädchen sobbed: ‘How awful!’” seems to answer the question. Another article in Time, dated to April 23, makes the position clearer by stating that “few of Ohrdruf’s burghers had ever been allowed to see” the camp. When forced to view it, one said, “It’s the work of beasts.” Further, it is the SS who were forced to clean up the bodies and bury them. Such descriptions can also be found in the Newsreel Nazi Death Mills, the first film images that Americans would have seen.

Hence, we can see that there was a confused depiction of who ought to be held responsible for the atrocities of the liberated camps. Although it might at first seem that liberating soldiers marched German citizens through the camps in a recognition of the guilt of the camp atrocities, upon closer inspection, this collective guilt seems to be something else. Instead, the liberators found them guilty not of the atrocities, but of association. Their crime was that their leaders had committed atrocities. Accounts often depicted their surprise or distress when they confronted the scenes of the camps. When seen in this light, these depictions align with other texts portrayal of the situation in Germany.

A number of cultural texts produced during or directly after the war suggest that the German people, far from being active participants in the crimes, were themselves victims of Nazi brainwashing, propaganda, or direct coercion. In one 1946 textbook, World History by Smith, Muzzey, Lloyd, the authors wrote that “Hitler proved to have an almost hypnotic power over his audience.” In the 1952 The Making of Today’s World, author R.O. Hughes stated that the Nazis “terrorized or hypnotized the Germans into being willing to take Hitler as their Fuehrer.” Other sources depict the situation in Germany in a similar fashion. For instance, in Disney’s 1943 production Der Fuehrer’s Face, Donald Duck, dreaming of life in Germany, is forced to work long shifts at an armament factory while also being bombarded with propaganda. Even more striking is Disney’s Education for Death: The Making of the Nazi in which a young boy is educated in German schools and undergoes shaming to orient him toward Nazi ideology. Ultimately, he becomes a member of the Wehrmacht and hates those who oppose Hitler. At that point, he and his unit are marched off to war as the scene fades into graves with swastikas.

Thus, during the war, the terms German and Nazi, although both were used when discussing atrocities, denoted different responsibility. Germans were certainly guilty, but only of allowing themselves to be seduced or coerced. They just needed to be reintroduced to freedom. Nazis, on the other hand, were the ones who committed the atrocities and, according to official statements and other sources, were responsible for the crimes which occurred.

To answer the question more directly, sometimes the term German might be used during the war, but when this occurred, the speaker likely spoke of the war itself rather than the war crimes. When speaking of the camps or shootings, most Americans seemed to have divided the Nazis from the Germans. This was primarily because in the West the German military and the war itself could be separated from the camps. In the East, where Soviet, rather than American or British, troops fought and liberated camps, the war and the atrocities coincided and could not be separated.