A conservative activist who criticizes what he calls the leftist domination of college campuses was struck with a pie Wednesday night at Butler University. David Horowitz, president of the Center for the Study of Popular Culture, had just started a lecture at Butler when he was hit. Horowitz's supporters followed the assailants out of the hall, and confronted them with what a witness called "pushing and shoving." However, the attackers got away. "There's a wave of violence on college campuses, committed by what I'd call fascists opposing conservatives," Horowitz said. "It's one step from that to injury."