A lot of Americans, left and right, will tell you the same thing.
When I was a young-un people were convinced the lessons of WWII would never be forgotten. How wrong they were. You listen to people these days spew about the "greatest generation" and the next day listen to them preach appeasement, isolationism and defeatism.
Not a big expert on pre-war Pacific political geography, and was always skeptical of these kind of claims but ... General Marshall was called to a post-war Congressional inquiry -seven- times and always had to disappear abroad on urgent business of high import to United States foreign policy. He never appeared. Clearly, he was not going to answer any questions about the run-up to war and it is likely that the war with Japan was precipitated.
There was nothing wrong with that as an aim (unless our own interests were not at risk) but it does mitigate Japanese guilt for unprovoked aggression or other non-Convention ‘moral equivalency’ charge.
As far at the future goes, I do not think Japanese re-militarization would be of any significance, any more than German re-militarization. It is much much cheaper to purchase the land than it is conquer it. East Prussia would be like East Germany in that it is cost-center and not a profit-center. Economically it is worthless - to the German state. To those who lost their ancestral lands, it is priceless. But that is another matter.
Japan’s only remaining territorial claims are the Kuriles and this is not going to be settled militarily.