Houston, Texas, is supposed to be the most ethnically and religiously diverse city in the United States. Its mayor, Annise Parker, is the first openly lesbian mayor of any major city in the country. She has recently supported an ordinance barring anti-gay discrimination in any business that serves the public and/or has contracts with the city. Nothing original about this: Entities from the federal government on down have issued similar rules. In Houston as elsewhere, there was a “religious exemption” clause–in other words, the bakery of a Catholic monastery that delivers rolls to the city jail may do so...