The Allied blockade ended after the Treaty of Versailles was signed, in June 1919.
The armistice was just a cease-fire - it was the end of the shooting war but not the end of offensive operations, nor was it the beginning of peace.
Without actual occupation of Germany - which would have meant a bloody resumption of fighting similar to the putative invasion of the Japanese home islands in 1945 - the blockade was the only way to force Germany’s compliance.
One way to think of the blockade is as WW1’s atomic bomb - it couldn’t be countered and eventually forced a military dictatorship to disintegrate.
The only government that "disintegrated" because of the starvation blockade was the Weimer Republic, albeit fourteen years lafter. It never recovered from the humilitiation of the peace treaty, which it had foolishly thought would be based on the 14 points (translated and airdropped before the Armistice). The pro-democrats were already in power in Germany by the time of the Armistice but the starvation blockade (condemned by the likes of Herbert Hoover and even British troops on the Rhine who thought starving German children was bad pr) continued for eight more months!
BTW, the mass slaughter of babies in their cribs and Japanese Christians in Nagasaki didn't accomplish anything. Truman received a surrender deal (e.g. the Japanese could keep the emperor) he probably could have had even before the bomb.