I've always surmised that a lot to do with the fact the atrocities occured on actual German soil. The evidence and remnants of the events and what transpired are distributed across the nation as a constant reminder. Would Germany associate itself with the WW2 Holocaust if it all exclusively happened off soil in invaded/controlled territory?

Like in Australia we are greatly more concerned about how we negatively impacted those who were on this land before us. Compared to our impact in other countries or the situations we force upon refugees off soil. So we discuss and go over the events and what transpired between us and the indigenous aboriginal people.

The United States is similar in having greater concerns for the concessions of Native Americans and minorities which were imposed into slavery. But isn't concerned for its involvements in coups or civilian deaths in ongoing wars.

I think the United Kingdom is a big one as well. Having spread and made such upheavel to so many reaches of the world under the history of its empire. Many having quite a few attrocities between them. But the UK doesn't reflect as much on that history that happened offshore.

Countries always seem to only hold themselves accountable for their actions at home. I think as a by product it lets countries like Japan feel they can gloss over what happened. Would Germany have had such a turn around if the events that transpired occured elsewhere? There were certainly other large impacts felt by the war for years that come into play, but the potential to live near or drive by the site of a concentration camp is a unique undeniable ownership of the events that happened. For the rest of all nations often what happens off soil is almost fantasy if we're not forced into accountability.

None of this isn't to say you shouldn't have an opinion on it. I'm not even disagreeing with the fact it is a shame that political leaders in Japan have intentionally glossed over it. But I just wanted to put out what I've been thinking on the topic for a while.