Marriage does not exist to benefit individuals couples. It exists to benefit society.
The fact that you as well as liberals in general seem to completely not understand this show that the institution of marriage has already been harmed.
Even if we buy that marriage is for society and not individuals, we need some compelling reason to deny it to those that society does not get benefit from. You also need a compelling argument that society does not benefit from gay marriage, I personally think it does. In the absence of such a compelling argument, society needs to treat them equal to all other relationships.
But I just have to know after reading this post - what is there to fear?
Truthfully, I don't really get it either. I know it is there, and it produces some startling reactions, but I'm not sure why.
Want to see it at work, go into your average bar and buy a guy a drink and wink at him. See if you don't get your ass kicked. Why? Why would he react violently to that? It is a compliment, no?
My personal guess is that it stems from many guys not being really all that comfortable in their sexuality, and maybe a little afraid of being treated like a woman (because, if they know it or not, they think of women as inferior.)