Nobody is attempting to justify anything. That is just how Dick wrote his novel. When Dick wrote TMITHC, the Nazi holocaust was well documented, still on people's minds, and could easily be extrapolated to Africa and so forth in an AH where they won WW2. Japanese crimes were far less widely known in America - especially the Chinese stuff. 1960's drug addled SF writers enamored with Asian culture, buddhism, Zen, Karate, the I Ching and other ways to expand oneself just didn't see the Japanese Empire in a particularly negative light. This lasted until fairly recently. I remember Spielberg's 1941. The Japanese submariners trying to attack LA are basically just fuinny and human - the Nazi officer on the Japanese sub played by Christopher Lee, however, was pure evil. It really took Chinese cinema to become mainstream for people to get another perspective on Japanese war crimes in WW2 and before.