[Lurking Libertarian]

No, you are missing the point. "Interfaith couples" are protected by the First Amendment, just as same-sex couples are now protected by the Fourteenth Amendment. That means they are protected from discrimination by the Government. No one is protected by the Constitution from any kind of discrimination by private parties; such protection exists only where there is legislation in force to that effect.

No federal legislation treats homosexuals as a protected class for any purpose. A few states have legislation treating homosexuals as a protected class for purposes of "public accommodations" (which is why there have been a small handful of suits against bakers and florists), but none of those state laws cover churches (and any legislation that attempted to tell churches who they must marry would be struck down as unconstitutional under the First Amendment).

My bet stands.

[dware]

No one is protected by the Constitution from any kind of discrimination by private parties

Tell that to business (or churches) that have race-segregated restrooms.