Discrimination: How dirty a word?

I have an essay in the new Commonweal about the Christian Legal Society v. Hastings Law School case. It's only available to subscribers, but here's an excerpt:

[W]hen is discrimination “wrong?”  Is there a difference between excluding someone because she is gay or black or female and excluding them because she refuses to affirm the immorality of homosexual conduct, the supremacy of whites, or the wisdom of patriarchy?  If there is not a meaningful difference in terms of the harm to the person excluded, is there a meaningful difference in terms of the harm to the group’s shared identity posed by prohibiting such exclusions?  More broadly, when does discrimination’s “wrongness” justify state intervention?  Most Americans agree that the state should act to limit discrimination in the provision of goods that are essential to self-sufficiency – e.g., employment, housing, and education – and that the state should leave purely private groups alone  – e.g., no one is clamoring for laws that would require the neighborhood bridge club to admit racial minorities.  But many discriminatory groups are not depriving anyone of essential goods, nor are they purely private.  A student group enjoys the resources of a state university.  A religious charity seeks access to state funding in order to compete with the other charities receiving such funding.  Where exactly should the line be drawn, and what values or harms help us decide that question?

We need to talk about why diversity is valuable, equality is essential, and discrimination is corrosive to the social fabric.  Even more importantly, we need to identify the conditions under which these propositions are true.  Given the vitriol that marks our political discourse these days, it is tempting to sidestep these conversations, but we cannot pretend that concepts – even our most cherished concepts – possess talismanic properties, as though they magically justify any project to which they are attached.