The demonstration was the idea of Tyronne Stoudemire, Hyatt Hotels’ vice president of global diversity, who is black. He poured Rauner a glass of milk — which he said represented the white men who sit at the helm of most organizations — and then squeezed a dollop of Hershey’s chocolate syrup into the glass. The syrup, which sat at the bottom of the glass, represented how diversity “sits at the bottom of the organization.”