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.
I think this is a net positive. I believe when people advocate for expanding the scope of what beliefs and behaviors government can enforce, they lack the imagination to wonder what could happen if you find your beliefs in the minority one day.
But the price of living in a society with diverse communities is that we occasionally have to hold our noses when people embrace shitty ideas. In fact, we have to defend their ability to do so.
It's not relativism because I wouldn't claim that every group or culture's norms and practices are equally right. I might think some of them are completely wrong. But I do hold that, so long as their wrongness doesn't go against the core norms and institutions of the nation, then we live and let live, with the caveat that people are also free to leave their communities and join others.
So far as I can see, this is the only pragmatic way to organize things, since people are going to disagree about important things and we all have to live together.