The crux of the matter to me is... so why did the studio/tog accept the job from this couple, did they not meet and arrange things?
If the studio actually didnt meet them and didnt know ahead of time what kind of ceremony they were taking pics of, thats one thing... its goes against that studios beliefs as people and a business model, and they didnt know it ahead of time.
But it sounds like they were the ones responsible for saying "no gay weddings"... dont take the job, then scoff at the point of transaction, they should clearly advertise their beliefs beforehand.
I smell a game of gotcha from the studio, itching for a fight... **** that, your job is to take pictures, if you object on certain grounds to given circumstances, that needs to be clearly advertised up front.
Otherwise, just take the pictures and take your money.