On a day of chaos at the University of Missouri — where both the school’s president and chancellor resigned after weeks of campus disruptions by students inspired by the Black Lives Matter movement — was also a day of media censorship. Following in the media-hostile tradition of Black Lives Matter, a student journalist named Tim Tai, who was working for ESPN, was accosted and intimidated by the crowd, who attempted to block him from doing his work. When he pointed out he had the right to be there, the mob continued to surround him and other journalists trying to report...