Alleged Charlie Kirk assassin Tyler Robinson appears to have been a member of a bizarre Steam group named “Read This If Your Gay,” a title that eerily mirrors the mocking inscription “If you read this, you are gay LMAO,” which was etched on a bullet casing at the crime scene. Steam is a video game platform that lets you play, discuss, and create games on your computer. The group’s profile featured cartoonish imagery, including anime-style characters, underscoring the meme-driven world in which Robinson and his associates seem to have operated. Incredibly, members of the group were issued a frantic warning...