I don't think anybody claimed there were reparations made after WWII.
The reparations forced upon Germany after WWI (combined with out of control Japanese, and to a lesser degree Italian, nationalism) are what caused WWII. Wilson's "Peace without Victory" was considered to be too soft by Great Britian and France (and the Netherlands, but they weren't nearly as passionate in their beliefs), and led directly to WWII.
After WWII, the Allies took a look back at history and realized that reparations continued the war in the eyes of the vanquished and decided they would take a more pro-active role in helping them rebuild as a nation. This not only provided fiduciary benefits to the Allies, but allowed them to foster trust and forge alliances with their former enemies, both in Japan and Germany.
When Japan was pushing for a seat on the UN Security Council a few years back, they did own up to torturing and abusing US POWs, but that's as close as they've ever come to acknowledging being anything but "honorable" defenders of their empire as far as I'm aware of.