One of the more infuriating experiences that ordinary social media users have occurs when people subjected to hateful or threatening speech report it to the platforms’ overseers and are told in response that the posts in question don’t violate their policies—an especially common occurrence at Facebook, despite its claims to be working hard to remove such speech. Facebook’s arrogant handling of these issues isn’t limited to just everyday users, though. Even one of the nation’s oldest and most influential civil rights groups, the Anti-Defamation League (ADL), gets the same treatment. Following up on Facebook’s pledge a year ago to ban...