While the three social media posts in question were political commentary rather than jokes, the arrest of Graham Linehan is only the latest arrest of a comedian as part of the global crackdown on free speech. For thousands of years, satire and parody have proven to be the most penetrating —and at times, irritating —forms of political speech. The co-creator of the U.K. sitcom “Father Ted” was arrested at London Heathrow Airport, allegedly over several social media posts criticizing transgender activists. For years, free speech has been no laughing matter in Europe and other parts of the world. In my book, “The Indispensable Right: Free Speech in an Age of Rage,” I discuss how free speech is in free fall in Europe, where the European Union is pushing for global censorship of social media, including American companies.