I think it's important within the pluralist framework to also recognize that we require conformance from all groups in more than just the small core. We require all groups to be law-abiding in action if not thought. Part of the democratic ideals is that if The People make a law, everyone will follow it, even as they campaign to change it. (Which glosses over some legitimate forms of protest, but this is an internet comment, not a book.)

Whether there are laws on the books that could be applied to this case, or whether there should be, I am not a lawyer or a politician, but American pluralism doesn't require blind acceptance of any practice of another group, even religious practice (polygamy, for instance?). The core of our shared system provides mechanisms for deciding whether a behavior is acceptable, prohibited or obligate.