Timothy Vaughn dutifully cheered the University of Missouri for a decade, sitting in the stands with his swag, two hot dogs and a Diet Coke. He estimates he attended between 60 and 85 athletic events every year—football and basketball games and even tennis matches and gymnastics meets. But after the infamous protests of fall 2015, Missouri lost this die-hard fan.

“I pledge from this day forward NOT TO contribute to the [Tiger Scholarship Fund], buy any tickets to any University of Missouri athletic event, to attend any athletic...