This is... interesting. On the one hand, the role/religion inversion is useful in freeing up the observer from tribal-line identities (liberals automatically siding with the gay couple, conservatives with the baker).
On the other, a union between two consenting adults is in utterly unlike socially-sanctioned pedophilia.
I'm not sure how I feel. But there is a constitutional right to the free exercise of religion, whether I like it or not.