To give a simple example, students are free to march with candles chanting, “No means yes, yes means anal,” in a park. The First Amendment gives them the right to do so. But no sane university would tolerate a student group marching through its campus shouting this ugly slogan (as some male students once did at Yale). The university would be entitled to institute disciplinary proceedings because the relationship — the entire relationship — between a university and its students is governed by the goal of education. Students are members of a university community dedicated to learning, and the university is entitled to enforce the obligations of community membership.
The limits on the university’s ability to regulate the speech of its students are therefore demarcated by the limits of its educational reach over students. Such limits do in fact exist. During the days of the free speech movement in the 1960s, for example, many demanded that Berkeley punish students who had participated in the (illegal) sit-ins in the South. Berkeley Chancellor Clark Kerr correctly resisted these demands on the grounds that the educational responsibilities of the university did not reach the students’ off-campus political activities.