Neuro-sama is a VTuber who streams Minecraft and the rhythm game Osu! on Twitch. But unlike most anime avatars, she’s controlled by an artificial intelligence program rather than a human being. That makes her catnip for the denizens of Twitch chat, who can prompt her to respond with all sorts of questions ranging from innocent inquiries to 4chan trolling. Within the first few streams, someone had already asked Neuro-sama about the Holocaust. “I’m not sure if I believe it,” she said. That was one of the more infamous clips that went viral online near the end of last month. Asked...