There isn't always a manifesto. The man who murdered 58 people in Las Vegas in 2017 didn't issue a statement about his worldview; if you think there must be a political motive behind his crime, you've got little to go on beyond some possibly-apocryphal comments he allegedly said before the shootings. And when there is a manifesto, it doesn't always find an audience. For every Ted Kaczynski or Anders Breivik whose words attract fans or even imitators, there's someone like Seung-Hui Cho, the man who killed 32 people at Virginia Tech in 2007. As J.M. Berger noted in a recent Atlantic article about murderers' manifestos, Cho left plenty of written and videotaped words behind, but these "were so inchoate that they stripped any veneer of meaning from his massacre."
And now there's the guy who just slaughtered at least 49 people in two New Zealand mosques. His manifesto emerges, dripping, from the memes-and-shitposts world of 8chan, 4chan, and similar sites. Parts of the document are obvious put-ons, even as the blood in Christchurch reminds us that the killer wasn't kidding about his lethal intentions.
Most of the manifesto is earnest. I see no reason to doubt the writer's racism, his fear of "white genocide," or his contempt for immigration. And no, the shooter's interest in environmentalism and his attacks on global markets aren't big twists; those aren't unusual sentiments in the white-nationalist world. He calls himself a fascist, and I believe him. It isn't remotely surprising that a man who set out to murder Muslims would have beliefs like this.
But the document isn't always so straightforward; at times the terrorist is trying to fuck with his readers. Like the part where he says that the black American conservative Candace Owens "has influenced me above all" and then adds that he has "to disavow some of her beliefs," since "the extreme actions she calls for are too much, even for my tastes." Or the part where he answers one of his own questions with the so-called "Gorilla Warfare copypasta," a string of ludicrous threats and braggadocio that Reddit types have been cut-and-pasting into conversations for nearly a decade. This rhetorical mixture of sincerity and sarcasm is common in the online spaces where white supremacists gather (and in more than a few other online spaces too). Now it's leaking into a terrorist's manifesto.
It didn't just appear in the manifesto: It showed up at the crime scene. At one point in his attack, right before opening fire, the killer said, "Remember lads, subscribe to PewDiePie." PewDiePie, a.k.a. Felix Kjellberg, is a popular YouTube personality, and several press reports on the massacre have pointed out that Kjellberg has flirted with maybe-ironic-maybe-not anti-Semitism himself. But what's more to the point is that the words "subscribe to PewDiePie" are themselves a meme. Reciting them before you shoot people is the internet-age equivalent of murdering someone while you repeat a Saturday Night Live catchphrase.
The fascist terrorist is also a fascist troll. Reading him is like seeing a Pepe meme carrying an actual gun.