I apologize i did not read that post (there are a lot on this thread and I come in for an hour or so, and don't get back here for another day.) so please bare with me.
Fair enough.
Your assertions are still rooted in the idea that people who identify as "gay" are a "people" just because someone is a demographic based on any sort of preference does not mean that they should get special privileges.
It's not a matter of gay people getting special privileges; it's a matter of them getting the same ones as everyone else.
And it's not a matter of identifying "gay" as a "people"; it's a matter of identifying a gay person as a person, and therefore the proper recipient of human rights.
Take for instance smokers, some people love smoking, they can't imagine quitting because they don't care about any possible ramifications (and not all people who smoke get cancer but, i digress). Yet, they are confined to smoke only in designated areas and are not allowed to smoke in certain places because, it offends people(they don't like the smell or smoke or whatever). This is based on a behavior and a preference.
No - not because it
offends people; because it
harms people. Smoking
offended people for centuries, but it only became illegal when it became clearly established that second-hand smoke causes serious and definite
harm to the surrounding non-smokers.
Sexuality is much the same, it is behavior and preference. it does not mean that we are required to change the definition of marriage to be "whatever you feel like" when marriage was instituted in all cultures as a way to bear and raise children.
Pregnancy and parenthood is the way to bear and raise children. It's been officially established in our culture for quite some time now (and unofficially acknowledged with a wink and a nod in virtually all cultures for all human history) that marriage is not necessary for this.
BTW - something just occurred to me: Joseph Smith is credited (if that's the right word) for marrying teenage girls as young as 14. Other LDS members here have excused this by pointing out that Smith didn't have children with any of these girls, and claiming that their relationships were a matter of material (or perhaps spiritual) support and protection, not sex.
Is this a fair assessment? Is it wrong?
Either way, either you're wrong about child-rearing being the only valid purpose of marriage or the founder of your religion entered into several marriages for invalid purposes. Which is it?
If you define marriage outside of that boundary (the reason it was instituted in the first place) then you have to also aknowlege other forms of "marriage" marriage to robots or poly-amorous relationships, marriage to primates or any animal that has the presence of mind to make cognitive decisions. You will be setting a precedent under the guise of "rights" when in reality they already have the same rights. just because their preference doesn't align with the law doesn't mean their rights are diminished.
Ah... slippery slope game. How about we look at things from the other perspective?
If your position is correct and child-rearing and marriage are inexorably linked, then this doesn't just condemn childless marriages; it condemns child-rearing outside of marriage.
Should we go back to the days where an unmarried single mothers are forced to give their babies up for adoption? Should there be some sort of penalty of law against parents who would raise a child while they aren't "properly" married?
And as to the slippery slope hypothetical (hey - you
can deal with hypotheticals after all!), answer me this: does a robot or a non-human primate have the legal capacity to enter into any agreement? If not, where does your worry come from? If the day came when chimpanzees or horses were owning property, signing contracts and serving as directors of corporations, I might agree with you that there's a risk that they might be able to marry as well... but I don't think any of these things will happen in the foreseeable future.
As for polyamorous couples... I suppose that's a possibility. It would have some major legal hoops to jump through and take a fair bit of political will that, IMO, so far isn't there, but I guess there is an outside chance that this will occur. However, I think this issue will go forward or not independently from whatever happens with same-sex marriage. I'm also rather confused as to why a Mormon would have an issue with polygamy, seeing how (AFAIK) your church teaches that God's okay with it in principle, it's happened in the past and it's happening in Heaven right now.