Homophobia makes no sense, but that doesn't worry the bigots. I mean, why would anyone choose to be gay? It is the way some people are born: I've always known this, and now medical science confirms it. I agree that those most vocal against gay rights are likely to be unsure of their own sexuality.
I've also worked out why nature decrees why some people are gay. It is my own hypothesis, but, well, here it is. In an ancient hunter-gatherer society, from which we evolved, men and women spent their whole time working to provide food and shelter for their families. But if more is needed in society than mere subsistence, some people need a life without those parental responsibilities - the musician, the artist, the holy person etc.
I've never understood why people feel the need to impose their own ways on others. And I don't understand how it is supposed to harm my own hetero marriage if gay marriage exists.
I think some folks out there, including former archbishop Carey, need to just grow up and read the science.