A new documentary accusing Arab professors of intimidating Jewish students has touched off a fierce war—of words—on the Upper West Side. Where does free speech end and bullying begin?Of all the political documentaries that have ignited controversy in the past year, Columbia Unbecoming is by far the shortest, sparest, and lowest-budget. Still, it quickly attracted an illustrious audience. It was first screened in March to a handful of university alumni. Then it was shown to a trustee, then to a high-level administrator, and then eventually to the university provost, Alan Brinkley. By October, Natan Sharansky, Israel’s minister for Jerusalem and...