Yes, absolutely. Suppose I had a gay child. If you think I would not love him or her with all of my heart, you have no idea as to what's in my heart. If you think I would disdain or reject him or her and his or her partner, you have no idea what's in my heart. If you think I would be angry with him or her, you have no idea what's in my heart. Yet, I would not agree that he or she should be able to legally marry, whether they are Mormons or not. And you know what? My gay son or daughter would know very well how much I love him or her. That would not be in doubt. Your belief that an anti-gay marriage stance is based on hate is dead wrong. It's not true for me personally and it's not true for my church. Are there some people in this world who hate gays? Yes. Do I? No. Does my church? No. Is hatred acceptable? No. Is it Christian? No. Is it Mormon? No. You are mistaken.
I'm not sure how you reconcile it with "love", but all of these are hateful acts:
- hand a homophobic landlord the right to evict your hypothetical son under a "no roommates" clause.
- deny your hypothetical gay son the right to participate in parent-teacher meetings for the child they're raising together.
- deny the right for your hypothetical gay son to visit his partner in the hospital, should the hospital feel like barring him.
- when your hypothetical gay son's partner dies without a will, hand his partner's half of their home off to a homophobic family member of his partner instead of him.
- even if his partner dies with his will in order and your hypothetical gay son ends up with the whole house, make sure he has to pay estate taxes on it so he might have to sell the house anyway to pay them.
When you support a same-sex marriage ban, you support all this and more. Effectively, you'd be telling your hypothetical gay son
"at all sorts of critical points when things seem their worst, I'm going to make things that much worse. For the rest of your life, I'm going to kick you when you're down." If you're going to call this "loving", then I can only assume you haven't thought through the full consequences of your actions or you have a very twisted view of what love is.