Eyck Freymann, an Oxford University doctoral student, was baffled to get a notice from LinkedIn this month informing him that his account had been blocked in China. The “Experience” section of his profile, which detailed his career history, consisted of “prohibited” content, he was informed.The social networking site owned by Microsoft Corp. didn’t explain more, but Mr. Freymann stated that he thought it was due to including the words “Tiananmen Square Massacre” in the entry for his two-year stint as a research assistant for a book in 2015.“LinkedIn is pulling people’s material off without telling them why,” he stated. “It was surprising because I am just a graduate student. I didn’t think I would have mattered.”The academic is one of a series of LinkedIn users whose profiles have been blocked in recent weeks. The Wall Street Journal identified at least 10 other individuals who had their profiles blocked or posts removed from the China version of LinkedIn since May, including researchers in Jerusalem and Tokyo, journalists, a US congressional staff member, and an editor based in Beijing who posted state media reports regarding elephants rampaging across China.