I posted this with a question mark in my title because something about it seemed off, if a bit cutesy. So Russ wrote a great commentary for me. See the comments, below. Thanks for your insights, Russ.
At the risk of being thoroughly discredited, I'll let my thoughts wander here:
I'm not entirely convinced it is "apples" and "oranges". Sure, selling a firearm legally to a customer is without intimate knowledge of what or how the gun will be used should not be against one's sincerely held religious beliefs. (If one has moral objections to guns, they probably wouldn't be selling them. Another question: a Buddhist works at WalMart and is asked to sell rifles in the hunting department; can he or she object to the assignment on moral grounds?)
Back to the other gun shop: What if the customer says, "I want to buy a gun to kill my wife." Now that would be an illegal act. Does the shop owner refuse to sell the gun? Call the authorities and notify them of a potential murder?
My feeling about public accommodations and public business is: If someone offers a service of any kind open to the public there should not be a moral litmus test for customers to pass; business owners should be able to refuse services if the customer is threatening, aggressive or using the business premises to conduct illegal activities, e.g. harassing other customers in a restaurant or selling drugs out of a motel room.
Otherwise, one's personal morals are none of the business owner's business. Leon and I bought the cake for our wedding at Costco. Did the Costco bakers or the Costco CEO "participate" in our wedding? (I wish they had, we might have gotten some expensive gifts!)
On the other hand, do any of us really want to spend our money or enter into a contractual agreement with a company or business that is openly and unabashedly anti-LGBT? Why would we put ourselves in such a position, unless to make a political statement?
Can atheists have "sincerely held (religious) beliefs" and if so would an atheist business refuse services to theists?
If it were not for the fact that LGBTs represent a minority, and most anti-LGBT business owners won't suffer significant financial losses by refusing services, this might not be an issue at all. Imagine if these business refused services to 90% of potential customers.
And, do these so-called christians with sincerely held religious beliefs serve customers who are divorced and celebrating a second, third or fourth marriage? Are there not biblical admonitions against such marriages?
Why are these controversies all surrounding the rights of LGBT folks to live our lives as we wish?
So much for rambling thoughts.
Perhaps John Corvino will weigh in on the topic. His logic is usually impeccable.