If the state of California does not require institutions such as hospitals and universities to allow unmarried cohabitation, there's no reason to require people to abandon their moral convictions because they enter commerce on some small level.
Religious rights in other states are being subjected to statutory control. However, the California (court) merely concluded that the Downey case centered on the state's constitutional guarantees of free exercise of religion. The state should have to show a compelling reason for denying religious rights. To rule otherwise would mean an individual would have to check personal morality at the door when entering the commercial arena.