Let's talk about ham. Some people will not eat ham--the Jews, obviously, but also the Muslims, and let us not forget vegetarians and vegans. This is fundamentally a religious objection, a matter of what they believe. Some of them are morally offended if you eat ham in their presence.
Were we, through some nutrition program such as the school lunch program, to insist that people with these beliefs eat ham, we would be discriminating against them, forcing them to violate their religious beliefs. We probably would not be allowed to do that under the religious freedoms clause of the Bill of Rights.
These people not only do not eat ham; they do not sell it, either. Were I to walk into a kosher deli and order a ham and cheese on rye, I probably would be shown the door rather quickly--it would be a highly offensive request. The owner of the deli has the right not to sell a product to which he has religious objections. It is not merely that he does not stock ham; it is that he believes the consumption of such a product is offensive to God. He would not serve me a roast beef and cheese sandwich, either, because it violates his religion, and he is perfectly permitted to do that--no one can say he has to serve the sandwich the customer orders if it is against his religion to make such a thing, even if he has the ingredients at hand. (He does not object to roast beef or to cheese, only to the combination.)
Now let's turn to the question of wedding cakes for same-sex weddings--and photography, and flowers, and catering, all the services that homosexuals believe they deserve to be able to get from whomever they want, that whoever they attempt to hire for the job has to accept the job. Yet they would agree that you cannot order a roast beef and cheese sandwich in a kosher deli and expect service. It is a matter of the religious opinion of the service provider superceding the wants of the customer. In the same way, if you are expecting someone to provide a wedding package for you and you are violating his faith, you cannot expect him to comply; he ought to be able to say, "I'm sorry, it is against my religion to provide products of that sort, why don't you try this other provider who is my competitor who does jobs like this and does them well?" If the provider is willing to pass on your business because he objects to the product you are ordering, you ought not to be able to force him or penalize him for doing so.
The objection will be raised that it is the same product, that a wedding cake or floral arrangement or wedding album is the same whether the couple is bride and groom, or two men, or two women. Is it? The wedding cake undoubtedly has a topper, and the traditional toppers are of a bride and groom, woman and man; should our baker be forced to carry or special order cake toppers he does not believe ought to be on a wedding cake? The photographer at our wedding choreographed many of the photos--the bride with bridesmaids, groom with groomsmen, family photos; the photos of the tossing of the bouquet, the removing of the garter, the embarrassing moment as the boy who caught the garter puts it on the leg of the girl who caught the bouquet--these are all pretty standard photos in the wedding album proofs. A photographer might not feel comfortable trying to adapt his wedding package to a situation in which bride and groom are perhaps more interchangeable. Wedding flower packages are based on the assumption that there are brides and bridesmaids, grooms and groomsmen, different flowers in a coordinated package.
I do not believe that anyone has claimed he would not sell flowers, or photography services, or baked goods, to homosexuals. The claim has been that these people will not provide wedding services designed for heterosexual marriages in service of what the providers consider a travesty of the purpose and function of the ceremony. If you want a corsage, a photospread of your children, a birthday cake, no one is refusing service based on sexual preference. Rather, they are refusing to provide services they do not ordinarily provide, refusing to adapt what they offer to suit something that is abhorent to their religious beliefs. Disagree with them, but take your business to someone else. After all, if the photographer says he does not feel comfortable shooting your wedding photos, you probably don't want his photos anyway.
Or are you really the kind of person who would order a ham and cheese sandwich at a kosher deli?