Let’s not confuse the issue here. By ‘how the Germans handled it,’ I refer to their de-Nazification and forthright acknowledgement of their actions in WWII. The Japanese don’t even acknowledge the rape of Nanking, IIRC.
As much as I want to agree with you that the Japanese should at the very least acknowledge the rape of Nanking, the problem is that we’ve already got a few Japanese who want the dark sides of their culture to be exposed specifically to promote a radical left-wing, globalist view to be imposed on Japan and are pretty much anti-American in their outlook.
Case in point: Hideo Kojima, the guy who created the Metal Gear series. Part of the reason why he created Metal Gear Solid 2 was supposedly because of the Japanese textbook controversies, with his taking the view that the darker aspects of Japan’s war time record be exposed for future generations to judge. And in his games, he promoted anti-Americanism since MGS2, and has also since at least MGS4 promoted total anarchy, Che Guevara (and this is despite the fact that had Che Guevara had his way back during the Cuban Missile Crisis, let’s just say Japan would probably have to suffer through Hiroshima and Nagasaki AGAIN) and May 1968 in France, LGBT politics, and a whole slew of left-wing revolutionaries in his games, denouncing the concept of national borders and also denouncing nukes or having a standing army, oh and also denouncing Guantanamo Bay. He’s actually given love to the FSLN and MPLA in his games as well. Heck, in various interviews, he makes clear he adheres fully to hard left-wing politics, at one point actually giving the hand sign of that Red Commando group in Brazil.
I’ve also seen similar stuff in Resident Evil, where in RE5 they had Chris Redfield, the hero, pretty much denounce America and Capitalism when meeting Sheva Alomar (though I’m not entirely sure whether they make any pot shots against Japan).
Now, if they have people wanting to expose the darker aspects of Japan WITHOUT the intention of basically turning Japan into yet another American education complex teaching hatred of their own country and advocating for left-wing politics, I’ll support it. Until then, them still having some pride in their country is the best I can get for now, even if they DO hide their darker elements. At least it beats Germany deciding because they’re guilty of Nazism in the past that they must allow free access to Syrian invaders despite it being very obvious that they have no intention of actually assimilating.