The greatness of war is a propaganda incorporated among the common people by warmongers. The poet’s aim is to raise voice against this. The poem ironically mocks at Kasper’s belief of a famous and great victory at the end of the battle. 
 
As the poem depicts it, the battle had caused a lot of destruction and loss of lives. But what had the common people gained from the war? Absolutely nothing. So how can it be called a ‘victory’ at all. It’s an ultimate loss and a defeat of humanity. It’s a defeat of innocence to the hands of some selfish people. That is why the little children Peterkin and Wilhelmine find no reasoning behind calling it a victory. They don’t know ‘what good came of it at last’. And anyone has no answer.