I don't see it as voting against homosexuality because of our religion, but because of our culture.
let me explain: If there is an election to allow gay unions and it passes, the effects of the election on our religion are very little. we still get to worship as we want, we still get to go to church, and read scriptures, and follow Christ the best we know how. But it does effect our society. the beauty of America is that we get to choose what we want to allow and what we don't want to allow into our society. In Idaho and in Utah (were i live now) the majority of the members of those societies don't want to allow gay unions. so they vote against it. It is the same in Wyoming (were i am from) but the reasons are completely different.
As far as my religion goes, I am content to allow consenting adults to do what they want as far as relationships go, that is their eternal right to agency. But, when it comes to how the society that I live in, that my kids grow up in, that I do my dealing day to day in, I prefer not to allow gay unions, that is why I vote against them.
It seems like a fine line, and to some people they may not be able to distinguish the two, but there really is a difference.