Your response is just nonsense. If it were a "nudist-themed" wedding, would you mind if she backed out for not wanting to expose her genitals to the guests? What if it's a "strapless dresses-themed" wedding, and her religion requires modest clothing? What if it's a "luxury you can't afford-themed" wedding? Is she supposed to go deep into debt because the bride wants a bachelorette party halfway across the country, and the wedding on a cruise ship? The mere fact that the bride asked her to participate does not mean that the "honored" person is required to go along with it. She's just required to be tactful in the way she declines.