Hmmm...good question. From a religious point of view, I think that many a minister (or perhaps congregation, or maybe church, or denomination, or whatever else they might call themselves) fears that they will be legally forced to marry gays against their beliefs. I think this is in large part what is prompting the outcry. To a smaller extent I think it is the folks who have religious objections.
Considering Canadian developments, I believe the fear of the religionists has some basis in truth, it is just a question of what they will do with it. <img src="/images/graemlins/confused.gif" alt="" /> Freedom of religion would guarantee them the freedom to refuse, yet would it protect them from repercussions, and should it?