To see this problem in microcosm, consider the case of American universities, which are notionally bastions of a depoliticized pluralism — miniature societies whose only official commitment is to free inquiry and intellectual diversity — but which somehow tend to end up containing fewer real divisions than the society they exist to educate and serve. Not that American academia isn’t pluralistic in some sense: There are plenty of competing ideas and warring schools of thought on college campuses, and plenty of forms of diversity represented in their faculties. But this is usually a pluralism of the already-acceptable, not the genuinely challenging, and as such it tends to evaporate when it seems to conflict with the (left-liberal, secular, liberationist) ideas that the academic community holds most dear.
You can see this dynamic at work with conservative Christian groups on a number of elite campuses right now — precisely because of issues related to “sexual modernity,” their ability to invite speakers, find advisers and gain university recognition is being chipped away at and constrained. (This chipping-away often involves demanding that religious groups promise not to discriminate on the basis of beliefs or behavior — a rule that’s allegedly intended to encourage pluralism within campus organizations, but has the actual-practical effect of reducing the space for ideological diversity writ large.) But even when the pressure is more informal, the effect is similar: Pluralism is absent or limited on our allegedly freethinking campuses precisely in those arenas where a robust theory of pluralism-as-social-good suggests it would be most valuable.