The Atlantic last week hosted a conference titled “Disinformation and the Erosion of Democracy” at the University of Chicago, where I’m a student. Barack Obama, Amy Klobuchar, Anne Applebaum, Jeffrey Goldberg, Ben Smith, Brian Stelter, and other boldface names studded the program, alongside many lesser-known members of the prestige press. They would gather, as a news release put it, to explore “the organized spread of disinformation and strategies to respond to it.” The Atlantic gabfest was billed as a space for rigorous dialogue, where the light of truth would scatter the darkness of disinformation. But the dialogue and criticism, it...