Leftists didn't learn anything form World War II. Left wing ideology is entirely deductive. All conclusions Newt mentioned were derived by leftists pre-World War II, including the reference to anybody to the left of Stalin as fascist.
Their whole not criticizing culture thing resulted from the left going to its Rousseau roots after the fall of communism. Rousseau had taught that science was bad, that technology was bad, that civilization was corrupting and that innocence was to be found among primitives. This is the the main reason leftists prohibit criticism of non-Western cultures, precisely because they fit the Roussearian mold of primitive.