I'm guessing it had something to do with passages like 2 Thessalonians 3:14: "Take special note of anyone who does not obey our instruction in this letter. Do not associate with them, in order that they may feel ashamed" (NIV).
It seems like some of the sentiment among some Christians toward being a photographer at or providing pizzas for a gay wedding comes from some similar sentiment. The train of thought seems to go something like this: "If I serve such a person in my business, I am condoning this sin." "As a matter of conviction, I must show my protest to such and such a lifestyle, person, or practice by refusing to conduct business with them."
2. Suffice it to say, I have serious questions about this line of thinking. For example:
- It shows remnants of clean-unclean thinking that the New Testament more or less abolishes in relation to the world (though not entirely in the church).
- It does not seem to fit the practices or trajectory of Jesus at all!
- It does not accomplish the same purpose as shaming in the New Testament world. In fact, it's effect is quite the opposite and spiritually harmful to the person doing the shaming.
Paul explicitly expects Christians to have interchange with sexually immoral people like adulterers in the world. Any comments he makes on shaming have to do with a small, tight Christian community.
You thus can't use Paul to argue to deny service in your business to someone you know for a fact is cheating on his or her spouse. Paul never expected the church to try to make the world follow Christian expectations.
b. Jesus of course ate with sinners. The Pharisees of the Gospels criticized him strongly for it. It's helpful from time to time to remind ourselves that the impulse to avoid "unclean people" was the practice of those who opposed Jesus and Paul. It was emphatically not the practice of Jesus or Paul. Indeed, it was the main reason they were hated by some.
c. Ultimately, the purpose of shaming in the New Testament is redemptive. In an honor-shame world, shaming is motivation for someone to change their behavior, to conform to the honor expectation. But it seems that most of the shaming today doesn't serve that sort of a purpose. It has the flavor of a protest rather than an attempt to reclaim. Indeed, in our day and age it probably inculcates the wrong spirit--one of vindictiveness.
3. The bottom line is that I think the "give them a letting alone" approach to sin is just plain bad theology. Sometimes it's well intentioned, no doubt. But it would seem to be another example of the Devil twisting people into doing something evil in the name of good.