Lets not get too far ahead of the narrative and argue that most Germans, or Austrians for that matter, automatically became wholesale ashamed or at least privately/publicly admit or own up to their own collective involvement in Nazi atrocities. During the 1950's, anti-Jewish sentiments remained alarmingly high in German-speaking areas of central Europe, many individual Jews were stating a decade or so after the end of WWII that Nazism "was a good idea, but poorly, terribly executed". It wasnt until the late 60's, especially 1968 with the rise of far-left, anti-consumerist student groups like RZ, Beider-Meinhof Gang, the Red Guards that the first serious, blunt often violent discussions about their parents' involvement or culpability in Nazi war crimes or intentional aloofness began in earnest, and during the scope of the Cold War in a place like West Germany, people and groups like Red Guards, Beider-Meinhof members were considered East German GDR communist Fifth Columnists and ignored even by many on the " New Left". You had a wave of domestic terrorist attacks in summer and autumn 1977 called the "Deutschen Aubend"---German Autumn. In many respects, ordinary German culpability in how they were willing or reticent accomplices to the Holocaust didnt hit hard in contemporary German society, intellectual and social cultural discussions until the late 90's and thats 55 years after the end of WWII. One constant discussion in immediate post-WWII German society was this metaphorical, figurative search for the " good :Nazi"---this example of a high-ranking Nazi Gauleiter who like most Germans of the time, kept his head down, did his job and wasnt singularly involved in actually killing anyone himself directly and after the war and war trials, his reputation was mostly impeccable and not too insidious.
After WWII, many Germans viewed Albert Speer, one of Hitler'a few close friends, architect, and his armaments minister, as maybe embodying that "Good Nazi" because he didn't look like a war criminal, particularly evil or sinister like Himmler, Goerring, or Georbels, and expressed at Nuremberg that he was sorry for the death camps, atrocities, etc. Of course, Speer at Nuremberg knew Allied prosecutors and judges didn't have or know all of what he really had done during WWII, his presence at a October 1943 Himmler SS speech privately acknowledging the true scale and horror of the mass-scale killings in the camps, he personally visited Auschwitz, Treblinka, Chelmno, Madjanek, and Sorbibor. If we'd known in 1946 what we would find out in the 1980's after Speer's death, he wouldve rightly condemned to death along with the other high-ranking Nazi bureaucrats. But, for a long time, many individual West Germans saw Speer as a believable, moral/ethical acceptable baseline they could follow or emulate until the inconvenient truth came out.
But, dont assume or believe that it didn't take most Germans decades to come to this realization and in some respects, its a process thats still working itself out. One can't compare post-WWII Germany to Reconstruction-era South or former Confederacy. The immediate political efforts to reconstruct, rebuild Southern cities, states under Pres. Andrew Johnson and Radical Republicans was a abysmal failure, endemic corruption, terrible communication, corrupt military governors, politicians, and oh BTW, many Southern major cities werent being rebuilt, many Southern states local and regional economies were neglected and not modernized, so many Southerners viewed the Union armies as an occupation force then a force trying to rebuild farms, homes, businesses, ease tensions, build a larger industrialized base in the Deep South. That power vacuum allowed for radical, white vigilante groups like the KKK, White League, Yellow Jackets to come to prominence and disrupt the pace of socio-political, economic progress.
I would argue we did a far better, efficient job rebuilding Germany and western Europe after WWII then we did the former Confederacy after the Civil War simply due to better socio-political and economic policies and planning, intertwined with the fact that unlike former Confederacy, most Germans realized explicitly they'd lost the war that caused the dire situations they were living under.