We rebuilt postwar Europe with the Marshall Plan. It didn’t include Japan.
We did it to prevent a repeat of the punitive Versaille treaty, with its destructive reparations that paved the way for Nazism to rise to power.
And to turn Germany into a strong ally that could keep the Soviet Union from expanding beyond the Warsaw Pact’s borders.
Okay, Japan was not part of the Marshall Plan, but we did at least as much for Japan, as we did for Germany. We even forced them to make abortion legal in 1947.
But at least Japan did not start immediately hating us.
Look up your history. The U.S. (and U.K.) were planning to be at least as punitive as 1919, if not more. It was only as the Cold War dawned that that changed.