By acting against the uncontrolled aggression of the Nazis in Germany, the world basically showed that they were ignoring the atrocities that were occurring in both Europe and China. Though in retrospect this may look like a thoughtless move, at the time it must have appeared that the angry military force of Hitler's Nazis was a bit more threatening to the rest of the world, where the atrocities were largely contained in their respective areas.
And though the results of WWII could not have been predicted by any means, the results surely make up for what was ignored before the war. The atrocities being committed in China by the Japanese were stopped, and the events in India change as India gains its independence shortly after World War II. In fact, many colonies gained there independence shortly after WWII, which is also a beneficial upside of the results of the actions of the world.
