In 1919, Germany and the Allied Powers signed the Treaty of Versailles. A major component of this treaty was Germany recognizing her role in WW1, and agreeing to make significant reparations, in the form of territory, money, and disarment.

In 1939, under Hitler's leadership, Germany invades Poland. Germany surrendered in 1945, and in 1947, the US began the Marshal plan, dumping a significant amount of money into Europe, with the 3rd largest benefactor being West Germany, receiving 11% of the total funding.

Empirically, caring about the wellbeing of the German people was a far more successful policy than punishing them.

Also, most of the Germans attempting to flee Nazi Germany were not Nazi's despite the fact that many countries (including the US) refused them entry out of feer of Nazis.