Obviously you didn't read the OP (I know it's long & for those who don't want to work intellectually, it just is too much).
My argument is that a child deserves to be raised by a mother & father, just as each child is created by such. It doesn't matter if the child is raised by an adoptive or biological mother and father. What matters is that the child is granted the right to the ideal balance of being raised by the 2 opposite sexes that naturally created the child.
I have a question on this point - you say a child "deserves" to be raised by a mother and father - but, what about all the deadbeat lousy good-for-nothing heteros who produce children then just abandon them? If two men or two women can offer a child a loving home, why shouldn't they be given the chance?
You see, this is the problem with the world today. All these heteros of shooting their DNA at each other, filling the world with children they either can't afford to raise or don't want. So, they abandon them, or just raise them in squalor and misery and they grow up to be criminals. You wanna hear some "stats" on existing gay households - number of children who grew up to be psycho murderers, zero. Number of children who grew up to cause holocausts, zero. All the worst people in history were raised by straight parents, or at least, parents in a "natural" marriage. So, when you think about it, using nature's track record might not necessarily be the best idea, wouldn't you say? A man and a woman DOES NOT precipitate the perfect balance.
I do think too that you criticize other people for not producing evidence or proof in support of same-sex marriage, while at the same time making sweeping presumptions of your own - such as the rather bizarre presumption that men and women are just happy and harmonious after marriage. My parents divorced each other twice and my mother is going through her third divorce with my stepfather. My good friends Blair and Ivan however, who've been together for 11 years now in true happiness and harmony, haven't been given the right to have even ONE wedding. Where's the justice there? And also, what kind of harmonious happy hope do you think WE had? I would have bloody LOVED to have a second mother, or a second father. It probably would have made for less conflict at home. People of the same gender seem to understand each other better.
Another thing, about the purpose of marriage and the meaning of marriage. Do you really so naively assume that marriage has just ALWAYS meant the same thing to everyone throughout the centuries? It used to be that divorce was unthinkable, and was an affront to the sanctity of marriage - this has now changed. having children outside of wedlock was considered an abomination - this has now (mostly) changed. Living together before marriage used to be unacceptable - this has now changed. If you think for ONE SECOND that marriage hasn't ALREADY changed beyond all recognition, then you're just being plain ignorant. And denying it now to people who are in loving, committed relationships, on the grounds of "tradition" is nothing but fascism and hypocrisy!
I've always wondered about this word "encouraged" when it comes to homosexuality. I mean...it just makes no sense. I have never ever in my life heard of anyone encouraging someone else to be gay. I've heard people encouraging ALREADY gay people to be open and come out...but is that "encouraging people to be gay"? I certainly don't remember making a choice about it. It seems to me that it's always straight people telling us that being gay is a choice. And yet, none of them can ever tell us when it was THEY chose to be straight. Funny that, isn't it? I mean, I remember making many choices in my life. July 27th 2011, I was sitting in Wagyu Lounge in Hong Kong (a popular restaurant), deciding between a steak or lobster salad, and I remember distinctly choosing the steak because it was my first night in HK and I should just go all out and enjoy it. That was around 7:40pm. Now, how is it I remember this choice like it was yesterday (as well as every other meal i had in HK during that 3-day jaunt), but not making such a life-changing choice as "being gay" - oh yes, I thought, that sounds fun, I'll be gay. Do explain this curious phenomenon - and perhaps enlighten us as to when it was you decided to be straight.