There's a lot to dislike about Germany's Alternative für Deutschland (AfD), the nativist–populist party that came in second in the country's recent election, but the party's battles against government suppression of its efforts to recruit supporters and criticize rivals aren't among them. Then again, members of the AfD aren't alone in being targeted for voicing disapproved ideas; across Germany, the U.K., and elsewhere in Europe, declining respect for liberal norms is breeding censorship and...