On university campuses across the country, from Mizzou to Yale, we have two noble forces colliding with explosive force.

One is a concern for minority or marginalized students and faculty members, who are often left feeling as outsiders in ways that damage everyone’s education. At the University of Missouri, a black professor, Cynthia Frisby, wrote, “I have been called the N-word too many times to count.”

The problem is not just racists who use epithets but also administrators who seem to acquiesce. That’s why Mizzou students — especially football players — used their clout to oust the university system’s president. They showed leadership in trying to rectify a failure of leadership.

But moral voices can also become sanctimonious bullies.

“Go, go, go,” some Mizzou protesters yelled as they jostled a student photographer, Tim Tai, who was trying to document the protests unfolding in a public space. And Melissa Click, an assistant professor who joined the protests, is heard on a video calling for “muscle” to oust another student journalist (she later apologized).