For a long time, while the bias in the media has always been obvious, I’ve always assumed that it was something in the water around the media coolers — that these people all lived in a self-reinforcing cocoon, marinating in confirmation bias, in which the correct attitudes were subtly rewarded and the incorrect ones not-so-subtly punished. If someone had told me that they actively conspired to drive the message, trumpet and even make up stories that served their narrative, and suppress those that didn’t, or undermined it, I would have said that it was both unnecessary and that even they...