Richard W. Collins III, fatally stabbed last weekend on the University of Maryland’s College Park campus, was as innocent as the 22 victims slain in the Manchester suicide bombing on Monday. Collins, an African American, newly commissioned U.S. Army officer from Maryland, was, like the victims of the Manchester, England, massacre, not bothering anybody. Slated to graduate from Bowie State University this week, Collins was simply out with friends enjoying himself. So, too, were those killed and wounded in Manchester. Authorities are investigating Collins’s death, allegedly at the hands of a knife-wielding University of Maryland student, Sean Urbanski, as a...