Tolerance, it appears, is not a one-way street. Since the rise of the gay-marriage movement, it has become fashionable to decry dissenters as haters and bigots, to attempt to write them out of polite society in the same way that the larger American body politic has rightfully rejected the Klan. Politicians thunder against Christian bigots. Media organizations put the words “religious liberty” in scare quotes, as if the expression of deeply held religious beliefs is a mere pretext, used to conceal darker motivations. And ideologues in state agencies give full vent to their rage, mocking faithful Christians as if they...