Nothing about this is liberal. When the Town of Greece identified itself with Christianity, it excluded Jews, atheists, and other religious minorities. And those excluded weren’t making an “interpretive choice.” The town board made the choice for them.
As Professors Rick Pildes and Elizabeth Anderson have shown in their classic work on expressive theories of law, the constitutional harm worked by official endorsement of religion is not about feelings. It is not something that minorities can avoid by cultivating thick skins. Rather, the harm is that the legal relationship between a government and its citizens has been altered, so that minorities now stand in relation to government as minorities, rather than simply as Americans. Government prayer renders them separate members of the political community, regardless of how they feel subjectively. Justice Kagan is careful about this in her dissent. Every time she describes the harm, she says that citizens of Greece “become partly defined by their creed,” or that the town’s prayer “alters a dissenting citizen’s relationship with her government,” or that the member of a minority faith “becomes a different type of citizen ... she stands at a remove, based solely on her religion, from her fellow citizens and from her government.” Constitutional harm of this type is not about the subjective feelings of sensitive minorities, and it is not something that can be avoided by desensitizing them.
After Town of Greece, there is nothing preventing the kind of religious-government alliances that have caused concern for hundreds of years: government favoring of the majority religion, explicit acknowledgements and endorsements of those favored religious views, implicit support for the ministers who hold those views, and statements of religious superiority seemingly backed by government imprimatur. In the Town of Greece, for example, ministers made statements implying that those who did not acknowledge Christ as the savior and God's role in the town were somehow inadequate, incomplete, and wrongheaded. Justice Kennedy compounds the problem by implying that failure to acknowledge the state's dominant Christian religious tradition makes you “unreasonable.” That is what Justice Kagan is worried about, and it should concern us all.
Government expressions of support for particular religious faiths aren't dangerous because they injure the sensibilities of the non-adherents—because they hurt our feelings; they are dangerous because they establish the framework, the rhetoric, in which persecution and shaming of non-adherents is made possible.
Incidentally, none of this necessarily makes religion special. Justice Kagan is right that “[t]he content of Greece’s prayers is a big deal,” but that is because, as she also recognizes, they touch on “a core aspect of identity.” Other types of government endorsement and denigration can do that too, such as racialized messages or statements about LGBTQ citizens, as one of us has argued.
The two main reasons for liberal acquiescence in Town of Greece are appeasement for the sake of a political compromise that the court (and just about everyone else) has already rejected, or else self-abnegation of the equal citizenship of religious minorities and nonbelievers. Neither of those options is attractive. Which makes some liberals’ willingness to accept them rather more surprising than the Supreme Court’s most recent assault on the separation of church and state.