I'm sorry, but I'm begging to see this whole argument as a tempest in a teapot. Frankly, I see the Christian proprietors of these various businesses as being somewhat misguided in the faith. For example, in the case of the pizzeria the owners are making the argument that catering a gay wedding violates their religious faith. I don't know what form of Christianity they practice, but Christ Himself dined and spent most of His time here on earth with sinners. Christians are charged with the responsibility of emulating Him. Hate the sin, but love the sinner as the current euphemism goes. In any event, gluttony is a sin. Does that mean, therefor, that the pizzeria will refuse to sell a pizza to a fat guy, as that would be supporting a sinner in his sin?
These folks must answer to their own sense of right and wrong of course, but I feel that they might be well served by thinking things trough a little more thoroughly when invoking Deity to justify their actions.