I have the highest regard and admiration for the small-business owner. They put their fortunes and everything they possess on the line every day.
Having said that, I do not understand why a shop owner would use their strongly held religious belief to deny their services to a gay wedding.
Wouldn’t your beliefs also prevent you from providing flowers and arrangements to those who believe that Jesus was a prophet but not the savior? That is the basis of the whole New Testament. What about those who deny the existence of God? Wouldn’t you have to require that your clients hold their ceremony in a Christian church so as not to expose you to conflicting practices?
If you had provided services to a gay wedding, would your church punish you in some way or even expel you?
A merchant provides product and services to the public for a fee. The business world is by necessity a secular environment. You are subject to laws, regulations and taxes, not your church’s moral requirements.