What happened to let's put all this behind us, what happened to moving past it. The truth is you can't move past it, because according to official history China is one of the victorious allied nations and Japan unconditionally surrendered. China is one of the SC5, Japan is not.
Why nationalize the islands, why name it, you could have done any of those since 1972, you could have made the islands officially part of Japan in 1972 or on wards, but you didn't. Because China at that time was weak, and there was no need to show off as the big man.
As I've said in my previous posts with you, The entire Senkaku Islands are Japanese territory. If we desire to name islets, then we have the right to do so. I have already , exhaustively at that, reiterated the notion of Terra Nullius.