Several weeks ago, an unknown 27-year-old named Shane Tamura walked into a skyscraper lobby in midtown Manhattan, took out an assault rifle he carried with him from Las Vegas, and opened fire. His killing spree resulted in the death of four individuals; it is the worst mass shooting in New York City for over two decades. Within hours, social media was awash with memeified images reminiscent of those that circulated last December, when an otherwise reclusive 26-year-old named Luigi Mangione walked to the New York Hilton Midtown, pulled out a 3D-printed pistol, and fatally shot UnitedHealthcare CEO Brian Thompson. Both...