The day these bakers, florists, photographers and, yes, even pediatricians refuse to serve a divorced couple or an unwed mother, I'll buy their "deeply held religious beliefs". Your sign must says "No Shirt, No Shoes, No Sin, No Service" and you must apply it equally.
You still don't get it. That's proof you cannot think outside your little box. Gays weren't denied service, the marriage event is what people have a problem with. The more accurate analogy would be a baker making a cake celebrating adultery, fornication, whatever. It honestly is not a complicated concept.
If you provide a service to straight couples, in some states and localities you must provide the same exact service to gay couples.
Baking a wedding cake for a fat couples would be celebrating sin (glutony)...but I've yet to a baker refuse to bake a wedding cake for fatties.
Photographing the wedding of a formerly divorced and remarrying couple would be celebrating a sin. Jesus actually spoke out against divorce...unlike homosexuality...but I've yet to see one of these "deeply religious" folks deny them services.
Not a single "Christian" business has tried to deny service to a non religious couple. That's clearly a big "no no" in the bible.
These folks are trying to use Jesus to justify their bigotry. Jesus doesn't like that sort of thing.