"My expertise is in shooting heterosexual weddings... which entails things like making the bride look beautiful, making the groom look handsome, making the couple look great together. A homosexual wedding has entirely different needs and special requirements. My expertise does not qualify me to properly portray the things a gay wedding photo shoot should portray, therefore it's best for all involved if you find a photographer who specializes in such events".
Mechanics are allowed to specialize in certain types of cars if they so choose, a programmer can specialize in certain programming languages, a chef can specialize in certain types of food, so a photographer should be able to specialize in certain types of weddings.
“My expertise is in shooting heterosexual weddings... which entails things like making the bride look beautiful, making the groom look handsome, making the couple look great together. A homosexual wedding has entirely different needs and special requirements. My expertise does not qualify me to properly portray the things a gay wedding photo shoot should portray, therefore it’s best for all involved if you find a photographer who specializes in such events”.
That’s the exact same argument that EHarmony made—they argued that they were experts in lining up men with women and knew nothing about the preferences for the queers. They lost in court.
I think it’s safe to assume these “weddings” are not real weddings but exist for the purpose of causing problems for such organizations.
If they were real, they would want to make sure they had the best wedding cake and photographs they could get as possible. It would be too tempting to be a baker to add, just a little extra salt, or just a little less sugar to these purchased cakes to ensure the recipient doesn’t make recommendations to their friends.