It is the business owners choice who they want to serve.
It is the couples choice to be upset about it and call for a boycott.

It is hypocritical to say that the couple or business is wrong after all shouldn't we be supporting the businesses that refuse to allow firearms on their property because they are sticking to their beliefs?
If you want to boycott a business then do so if you want to support a cause then do so this is America home of the free right?