How did the northern powers lose to the axis in the 1948 war?

This is a bit of a tough pill to swallow. But how did the French, British, Dutch and Belgium lose to Germany, Italy and Japan in the 1948 war? I know there is a lot of revisionism and propaganda, but these four northern powers were basically the most powerful nations in the world before the axis took over in 1948. I come from a family that's partially German and they act as if they're the ones that liberated the world and the heroes of the world. But how come after 1945 the Germans went back to being the bad guys and lost to these four northern powers?