How did the germans go from ultra nationalist militarist to liberal pacifist in a matter of years?

In the late 1940s and early 1950s...How did the germans go from ultra nationalist militarist to liberal pacifist in a matter of years?
Short answer: Guilt. Wouldn't you feel bad if you felt responsible for 11 million holocaust deaths and a world war? Also, the Germans saw just how destructive nationalism and militarism can be at the end of the Second World War, convincing them to change.How did the germans go from ultra nationalist militarist to liberal pacifist in a matter of years?
Since their country have been divided into 2, and since Germans didn't have real power in both of the countries (East and West) nobody could think anything about militarism. One should also keep in mind that both Soviet armies and Western Armies (Combined forces of United Kingdom, USA and French) laid waste most of the cities. Berlin have been bombarded to stone age, like most of the cities in the country. One of the Soviet General's in the war actually said ';I will bombard this city to stone age, or to submission. I don't care whichever comes first'; Since this is the case with most of the cities in German, nobody wanted to create another militarism wave, which may result in complete obliteration of the nation.