It is all too simple, really: it is none of our business what people do with their lives as long as no one else's rights are infringed.
I am not at all disturbed by two people in love who want to get married, be they man on woman, woman on woman, or man on man. It is within their fundamental human rights, it picks no one else's pockets, and it steps on no one else's shoes. What do you care if I marry the person I love and that person turns out to be man? How is that going to affect your indoor plumbing? How is that going to burn down your house?
I would be a terrible, terrible father if I took that happiness away from my child. That joy of marrying the person you love only comes to us a few times in our lives. Why would I want to stop my child from being who he is and from doing what will make him a happier, healthier human being? If you think that is twisting what is wrong to make it right, then I think you have a twisted understanding of love, decency, and humanity.