Is Gay Marriage Simply "Masturbation and the Pursuit of Pleasure"?

From time to time, I tend to get into political discussions and debates on Facebook. Shocking, I know. I recently made a post on homosexuality and why people hold the bigoted views they do about it. I eventually commented on how the religious folk at Franciscan University almost unanimously oppose same-sex marriage. Another commenter posted the following in response.

I suspect this person meant to say that homosexual activity doesn't meet the definition of sex. So, is this right? Is gay marriage nothing more than "masturbation and the pursuit of pleasure"? Why no, no it is not. I wrote the following in response, with the accompanying video:

So what should the alternative be then? Are infertile couples not really married? Should they not be allowed to get married? Should the law be that if you get married you have to have kids? Marriage is about more than just sexual pleasure. It's because people love each other and wish to express it as openly as possible. They want their union to be legally recognized, to be able to visit each other in the hospital, file income taxes together, make medical decisions together. And, btw, adopt kids together. That's the other thing; gay couples ARE having kids, e.g. adoption, donor insemination, etc. The same alternative routes available to straight couples are available to gay couples too.

The so-called "natural purpose" argument is a load of bollocks as well. Yes, the "natural" function of sex is technically procreation, but since when have we only stuck to what's "natural'? Cause the reality is that we defy nature all the time. Pacemakers, artificial limbs, glasses, hurricane-proofed homes, etc., all defy elements of the natural world and are themselves unnatural. Yet you won't hear anyone saying any of those things are wrong, so why say so of gay marriage? Gay marriage is consummated the same way straight marriage is; they have sex. And it may not be the same kind of sex you have, but ultimately everyone has sex there own way anyway. There's no one right way to have sex, and people's personal preferences are their business and no one else's.

And from the Franciscan point of view, gay marriage isn't seen as real marriage because their book tells them homosexuality is wrong. Yes, the same book that says the earth is flat and held up by pillars, condones slavery, and favors human sacrifice, surely must have gotten it right about homosexuality!