Baraboo, Wisconsin, population 12,000, was once the winter quarters of Ringling Brothers Circus. Otherwise its single claim to fame is its town slogan: “Valuing differences in identities, beliefs, and perspectives.”

The town got a surprise last year when a photo emerged showing Baraboo High School students giving the Sieg Heil salute. To be fair, only male students were pictured, and one refused to give the straight-armed salute marking allegiance to Hitler and the Nazi Party, but mos...