If you are a Christian and this is sincerely against your faith, why not form a co-op with Christian church(s) that do not recognize gay marriage. For nonmember's, or people who are not members of the churches involved, the co-op accepts the work, obtains the details of what the customers want and assigns a provider. Nonmembers pay a fee and the co-op has the option to either assign a member provider or sub contracts to outside providers. It is also possible that within the co-op, there is a provider that has no issue with providing gay services. However, to be member provider or just a member, you have to affiliate with a church.
The co-op has the contracts with other service providers who pay a small service fee for the referrals. The co-op collects a processing fee for referrals, membership fees and a nonmember's fee. Those fees are paid out in shares quarterly to co-op providers. If you are gay and you want a specific photographer just to create a court case. Sorry, the co-op assigns the photographers or subcontracts the work. You are hiring the co-op not a specific provider in the co-op. No doubt some gay couple would hide their intent, hire a the co-op and then change the requested service from a standard wedding cake to a gay pride one. The provider then refers the customer back to the co-op offices because they cannot make changes to the requested service. The co-op then refers the request to a different provider due to the changes made outside the signed agreement. That's the legal aspect I am not sure of.
It could be tough because you would not have off the street customers coming directly into your businesses. They have to go through the co-op offices. The co-op then screens the work requested either accepts the work in house or subcontracts it based on an agreement the purchasers signs. If a cooperative builds a reputation for quality service people will use the service. One stop for wedding photographers, bakers or a handyman.
I am sure there could be legal challenges, but I remember reading about a denial of service that was legal because the plaintiffs were not members of the cooperative. I just do not recall the details. Until sanity prevails this may be (or not) a course of action.
brilliant