The purpose of this scene is to remind the audience that genocide was not perpetrated by barbarians in the early stages of development of man, but by the most advanced peoples on the planet, who had already produced three of the greatest minds in music in all of human history: Bach, Beethoven and Mozart.
It was not the uncivilized that killed over a million children in the Holocaust for the "sin" of being Jews, Slavs, Gypsies, or disabled and sick Germans, it was the people of Bach, and Mozart, and Goette, and Hertz, and Kepler, and Max Planck.
This is an important lesson, because a man who has nothing doesn't mind losing the little something he had. It is because the German people had so much pride in their own identity, that, when they suffered defeat in World War I, a nation as advanced and civilized could commit so many attrocities - in rage.
It shows why humiliating anyone, even someone defeated, is inhumane and how for some people, even death and crime is preferred over dishonour.
But it also shows how the best of us, the smartest, the brightest, and fastest and the most beautiful, is mere few decisions from chaos and the darkness all human beings are capable of unless we make the right choices to accept responsibility instead of scapegoating others, to do justice even when confronted with overwhelming odds and injustice against us, and to never be so attached to our own ego and material things that we lose our minds when they are taken away.