Are you saying that Jesus would attend an event where two men pretended to get married?
Well that's an interesting question but not exactly on point. Invited guests are one thing. Certainly performing the ceremony is another. All of those functions "endorse" the ceremony so to speak. So I'm not sure it's the same thing exactly.
I submit the "hired help" like caterers and photographers and florists are something else entirely. They all have the right to deny the business, or certainly should have that right. I don't know that these guys, or gals, which ever they were, had any intention of actually using this firm. I think they were trying to be denied to make the stink out of it they did.
I would also point out one other thing: a professional prostitute was the single person chosen for the eternal honor of being the first to see the Risen Christ. Think about that. You got a problem with that?