The coward who gunned down 49 Muslim worshippers in New Zealand left behind a white-nationalist screed rationalizing his mass murder as a necessary act to preserve the white race.

The manifesto is striking for its trolling—its combination of fanaticism, insincerity, and attempts at irony. The killer was particularly obsessed with the idea of “white genocide,” a term that does not actually refer to mass murder, ethnic cleansing, or even violence, but to the loss of political and cultural hegemony in countries that white supremacists think should belong to white people by law. The theory of white population decline is innumerate nonsense; as The New Yorker’s Jelani Cobb writes, the conspiracy is a kind of projection, a paranoia that the past genocide, colonialism, and ethnic cleansing forced on the West’s former subjects will be visited upon it.

Although the manifesto itself was written in the distinctive vernacular of the far-right internet, there is nothing new about white supremacists trolling. The Nazis were dedicated trolls who weaponized their insincerity to take advantage of liberal societies ill-equipped to confront them. This was not done just for political advantage—rather, the insincerity itself was a moral act, an expression of contempt for the weak.

The original Nazis were open about their intentions, but their strategic insincerity created a fog of doubt that allowed observers to avoid the obvious. In 1922, The New York Times infamously declared that many believed “Hitler’s anti-Semitism was not so genuine or violent as it sounded, and that he was merely using anti-Semitic propaganda as a bait to catch masses of followers and keep them aroused, enthusiastic, and in line for the time when his organization is perfected and sufficiently powerful to be employed effectively for political purposes.” In 1930, even after the Nazis had become the second-largest party in the German legislature, the Times assured its readers that “there is no present basis for assuming that the Nazis will attempt to make anti-Semitism a militant issue in their legislative program.”