Hundreds of students walked out of Harvard University’s commencement ceremony on Thursday morning as degrees were conferred, while hundreds chanted “Let them walk!”, a reference to 13 student protesters who were not allowed to graduate after a vote Wednesday by the Harvard Corporation, the university’s governing body. The walkout was a jarring reminder of continuing unrest on the Cambridge campus, on a day when more than 9,000 graduates and their families were gathered in Harvard Yard for...