One of the reasons we can’t have nice things these days is because too many people refuse to see gray areas. You either agree with them or you’re the enemy. Moderation and compromise are not virtues to these people.
There are many people who disagree with gay marriage and gay rights who are decent, honest, and well-meaning people. They are not evil. 
They are just ignorant — ignorant of the harm they are causing, ignorant of what it means to be gay or lesbian. They have been misled by their religion and their leaders. I suspect that these people, like many, just haven’t yet realized that society has changed; that their views are not acceptable; that they need to re-examine what their religion is telling them. This does not come easy.