"Many American pundits seem to firmly believe that the country stands at a precipice in which young, left-wing college students and recent graduates are the leading edge of a rising tide of illiberalism that comes in the form of ‘political correctness’ and poses a clear and present danger to free speech and rational discourse,” Vox co-founder Matthew Yglesias wrote in March 2018. “It is so accepted that there is a growing climate of authoritarianism,” he continued dismissively, “that whether or not individual examples are true is fundamentally irrelevant.” Fast forward to June 2020: “I am going to have to admit I was wrong and the excesses are spreading,” Yglesias wrote this month in a series of now-deleted tweets. “I stand by a lot of my criticisms of the anti-PC discourse of five years ago. But...