Study involved 679 US liberals and conservatives rating fake Facebook profiles. Profiles featured liberal or conservative views on Trump and socialism. Own-ideology profiles rated higher on professional traits, character, and hireability. Negative bias against opposite ideology was three times stronger among liberals. Liberals rated conservative profiles far more negatively than conservatives rated liberal ones. Leftists demand censorship despite claiming tolerance. Conservatives face demonization as climate deniers or Putin supporters. Frankfurt School's Marcuse argued tolerance only for the left. Daily experiences confirm left-wing intolerance.