But Germany was almost completely stripped of its resources after the Versailles Treaty. They had to pay the allied forces a ridicules amount of reparation after WWI. In that essence, they too had to invade "neighboring" countries for resources to essentially pay the allies.
In fact I would even to go as far to suggest that Germany had more of a reason to invade its neighbors, as the Japanese were on the winning side of WWI and gained a lot in Asia due to the treaty of Versailles. They were quite simply greedy and wanted more resources to expand their empire like the Europeans did prior WWI.
Not to mention, China (Nationalists: the controlling Government) already have a country of their own, and were planning to remove the communists so I doubt it was in their interest during that time, to try gain International support like the Jewish community did, as they were more interested in gaining military support from the US to remove the communists than to complain about the atrocities committed by the Japanese.
And, even after 1949 when the Nationalists were defeated and exiled, the communist government were not recognized as the official Chinese government (it didn't happen till 72), so even if they complained about Japanese atrocities in China, no one really listened to their complaints about their suffering until 1972, by which time was 30 years after the war...
edit: that and Chinese people are more about getting on with life then complaining about that huge chip on their shoulders unlike some people...
Nazi Germany was relatively humane in their conquest/empire building, but 100% evil in their genocide of Jews and gypsies. Japan was much more vicious in their invasions.
Not defending nazis in any way shape or form, but there's no wiki article for "the rape of paris" or "the rape warsaw"
http://en.wikipedia...._Nanking_(book)