By the time my wife and I got to Kassel to see the latest edition of the Documenta — the once-in-five-years event that, in the contemporary art world, rivals the Venice Biennale for direction-setting importance — its centerpiece had been removed from public view, its director had resigned in disgrace and the German government was promising to step up its supervision of the exhibitions to follow. The scandal that engulfed what the German Jewish newspaper, Juedische Allgemeine, dubbed “Documenta of Shame” has implications that reach beyond the borders of Germany and the contemporary art milieu. The Western world, with its...