Same-sex marriage and freedom of association

One reason often given for opposing marriage equality is that government should not force caterers, florists, tour-bus operators, and the like to provide services in situations that would violate those service providers' religious or moral beliefs. While I believe in equal rights for same-sex couples, I agree that the service providers should not be forced to violate their beliefs. People do not forfeit their freedom of association by disagreeing with me. Also, competitive pressure provides an obvious remedy; if one bakery refuses to take my money, it thereby hands a competitive advantage to another bakery that will. Finally, I do not see the point of forcing people to take my money if they do not want to do so.  In short, since freedom is not a zero-sum game, we can accommodate both equal protection of the laws for same-sex couples and others' freedom of conscience.

On the other hand, I am still waiting to hear a cogent reason why freedom of association applies only to those who oppose same-sex marriage and not, say, to those who have an equally sincere opposition to remarriage after divorce in the absence of an annulment, or in other words why opponents of same-sex marriage deserve a special privilege.  Cherry-picking fidelity to principle is not fidelity to principle at all.

I like to raise that issue with those Catholics who oppose marriage equality on the ground of freedom of association, especially those who believe in their church's teachings against some forms of marriage that secular law allows. They either throw out a red herring or play the persecution card.