Why is Japan the only developed country in Asia (read carefully please)?

Immigrants from almost all Asian countries (including India) seem to do well in America. Why is Japan the only one that is rich? After all, they were the only one to declare war on America, unless you count Vietnam! I know America helped to industrialize Japan along with Germany, Israel and other countries after World War II. But that raises another question: why did America do so much to help countries that were hostile to it? Were the Russians/Soviets really an enemy? Why have we let them starve to this day? Why do we let Africans starve and even their descendants in our own country? If America actually thanked the communists for their help in fighting the Nazis, would the Cubans/Vietnamese have left us alone?