Morton Schapiro is president of Northwestern University.

College presidents have always received a lot of mail. But these days we get more than ever. Much of it relates to student unrest, and most of the messages are unpleasant.

Our usual practice is to thank the sender for writing and leave it at that. The combination of receiving more than 100 emails and letters a day and recognizing that the purpose of many writers is to rebuke, rather than discuss, leaves us little choice about how to respond.

But that certainly doesn’t mean we don’t think long and hard about the issues being raised. Some writers ask why our campus is so focused on how “black lives matter.” Others express a mixture of curiosity and rage about microaggressions and trigger warnings. And finally, what about those oft-criticized “safe spaces”? On this last topic, here are two stories. The first was told to me privately by another institution’s president, and the second takes place at my institution, Northwestern University.

A group of black students were having lunch together in a campus dining hall. There were a couple of empty seats, and two white students asked if they could join them. One of the black students asked why, in light of empty tables nearby. The reply was that these students wanted to stretch themselves by engaging in the kind of uncomfortable learning the college encourages. The black students politely said no. Is this really so scandalous?

I find two aspects of this story to be of particular interest.

First, the familiar question is “Why do the black students eat together in the cafeteria?” I think I have some insight on this based on 16 years of living on or near a college campus: Many groups eat together in the cafeteria, but people seem to notice only when the students are black. Athletes often eat with athletes; fraternity and sorority members with their Greek brothers and sisters; a cappella group members with fellow singers; actors with actors; marching band members with marching band members; and so on.

And that brings me to the second aspect: We all deserve safe spaces. Those black students had every right to enjoy their lunches in peace. There are plenty of times and places to engage in uncomfortable learning, but that wasn’t one of them. The white students, while well-meaning, didn’t have the right to unilaterally decide when uncomfortable learning would take place.

Now for the story from Northwestern. For more than four decades, we have had a building on campus called the Black House, a space specifically meant to be a center for black student life. This summer some well-intentioned staff members suggested that we place one of our multicultural offices there. The pushback from students, and especially alumni, was immediate and powerful. It wasn’t until I attended a listening session that I fully understood why. One black alumna from the 1980s said that she and her peers had fought to keep a house of their own on campus. While the black community should always have an important voice in multicultural activities on campus, she said, we should put that office elsewhere, leaving a small house with a proud history as a safe space exclusively for blacks.

A recent white graduate agreed. She argued that everyone needed a safe space and that for her, as a Jew, it had been the Hillel house. She knew that when she was there, she could relax and not worry about being interrogated by non-Jews about Israeli politics or other concerns. So why is the Black House an issue in the eyes of some alumni who write saying that we should integrate all of our students into a single community rather than isolate them into groups? I have never gotten a single note questioning the presence of Hillel, of our Catholic Center or any of the other safe spaces on campus.

I’m an economist, not a sociologist or psychologist, but those experts tell me that students don’t fully embrace uncomfortable learning unless they are themselves comfortable. Safe spaces provide that comfort. The irony, it seems, is that the best hope we have of creating an inclusive community is to first create spaces where members of each group feel safe.

I suspect this commentary will generate even more mail than usual. Let me just say in advance, thanks for writing.