A scrum formed, with Segev at its center, according to multiple videos of the incident recorded by bystanders and a news helicopter. There was bumping, bickering. Minutes later, Segev walked away. No one was injured. Police officers standing nearby did not intervene. As Segev stepped over and around the bodies, other demonstrators approached, and then surrounded him. One said, “Get out, get out, get out.” Last October, Yoav Segev, a Harvard Business School student, walked through a pro-Palestinian demonstration on his campus. He used his phone to video record protesters who were lying on the ground as if they were...