I read the whole thread and didn’t see a single argument about what good would have come from that. I think you’re looking at this from a very removed point of view that lets you forget the actual individuals involved. I’m German. Let me introduce you to my grandparents and let’s see how they would’ve fared under your proposed processing:

• Grandpa A was drafted at the end of the war, he was 13. He didn’t want to be there and plotted a “genius” plan with his two buddies two lie to his general about a super important mission from the general next town and run off. He probably only survived that because his general wasn’t in the mood to shoot him on the spot.

• Grandma B wasn’t drafted obviously, she worked in (basically) social services while WWII because she actually was a supporter of the Nazi party and felt like that’s how she could do her part. She didn’t commit any atrocities, probably simply because as a woman she never got anywhere close to the front.

• Grandpa C was a party member. He didn’t want to join at first – we still own a news paper page where he (and a few others) were openly shamed for refusing to join party and front. After his brother, who had turned down an SS position, was transferred to an extra risky combat unit as cannon fodder and died on his second day, he caved. I can only assume that, as a soldier, he actively participated in the fighting. He tried to disobey where easily possible, but he didn’t desert. When his general told him to “take care” of a woman he abused, he brought her away from the front, pointed her to the nearest town and told her to flee.

• Grandma D didn’t do any of that, but she was proudly engaged to a Hitler Youth leader (who thankfully died, so she met my grandpa after the war). While WWII she absolutely was a Nazi, but she didn’t actively do anything that would mark her as such. She got into a personal crisis after the war when she stopped lying to herself about this horrible system she had supported. Until the day she died she was convinced she would go to hell.

Killing every active supporter, as you suggested, would have both my grandpas executed, although they both condemned what was happening and, limited by their sparce abilities to do so, tried to disobey. My grandmas would’ve ironically been spared, even though they were (when it comes to their attitude) more Nazis than my grandpas. Neither of the four were Nazis at later points in their life, I’d like to add. And the generation after them would have never existed - an anti-nationalistic, anti-patriotic, highly political, highly critical and socially active family, influenced by traumatized men and rueful women.

So it would have achieved nothing. I'd argue the world would be even worse if that would have been humanity's answer to WWII back then.