The question is whether this right of sincerely advocating that same-sex marriage should not be condoned, and seeking to teach these principles, etc., extends to Christian business owners who refuse to provide a service for a gay marriage, or to a public statement of the same beliefs as opposed to merely confining it to their private lives.
In the majority of states, homosexuals are not a protected class so you are free to discriminate against them. This is being dealt with at the state level.
Also, a business is not a religion. If your religious beliefs prevent you from running a legal business, then you need to find a new business. Freedom of religion does not extend to commerce.