That won’t work any more as there are now religious orders of the Christian nature that have now accepted doing homosexual weddings.
You’re free not to accept this or that sect’s interpretation of holy matrimony. If you disagree with it, you don’t have to bake the cake. There’s nothing in the law that defines holy matrimony, only marriage. Holy matrimony is purely a religious concept and is distinct from the state sanctioned legal arrangment of marriage.
I wonder if this would hold up in court or if it would be deemed a frivolous evasion.