1. "Different rules apply. But either way, religion need not enter into it."
I Agree.
2. "Hetero-relationships (individual freedom) have always been supportive of a better future society by producing contributing members of society, so states have acted to encourage stable, creative families by establishing secular marriage (state action)."
All relationships are indicative of individual freedom; marriage was never delineated in the constitution. Nor were friendships, we were given the right to live our lives openly and without fear of retribution.
Our society/culture decided what marriage should be and chose to restrict it to their view of the world, indifferent to the hopes and dreams of others. I believe your characterization of marriage is personal to your vision. That's fine, we should all have the same rights as you. The constitution doesn't give you or the states the right to define personal and family relationships. All relationships can produce contributing members of society. Gay couples have the means to procreate and be contributing members of society. Believe it or not gays have been contributing to our society since we became a nation. Quietly of course or they would have faced terrible retribution. It is well past the time for us to correct this notion that we can oppress others to our world/religious views.
3. "The Left sees no need for a stable family, since the state should provide for everyone in need. Given that approach, I'm not surprised things have slid to you supporting giving marital endorsement (state action) to homo-relationships (individual freedom)...all while the Left argues there is no slippery slope"
I would like to ignore your first sentence, it's arbitrary and can be debated on another day. At any rate it is what it is. Marriage has evolved socio-culturally for centuries in our land. In the early nineteenth century, married women in the US were legally subordinate to their husbands. Wives could not own their own property, keep their own wages, or enter into contracts. On the death of their spouse wives did not exist legally, they could not own property, whether earned or brought in to marriage or have any rights to their children. As a society we have evolved away from this persecution of American citizens. Has it been a slippery slope? I would suggest not, it is an evolution of attitudes to all of our people not just some of them. We have grudgingly given equal rights to all of our citizens for almost 250 years. I believe that is healthy for a society and nation.
4. "There is no reason for the state to endorse any relationship. Marriage has always been about the children, not about the couple. The Left's fundamental misunderstanding of the purpose of secular marriage has led to them trying to redefine marriage."
Your first sentence makes no sense. Are you suggesting states should stop endorsing all relationships? What would we call them? Partnerships?
As for "Marriage always being about the children", I disagree. Marriage defines a unique relationship between two individuals, which will grow and determine what their future will be as a couple not by the state. I was remarried after my wife died and well past the expectation of children. I was blessed with another wonderful bride. Our marriage allows us to share our wealth and our health legally. If we weren't married her children or mine could determine our decisions at end of life. These are vital life choices and every relationship deserves the exact same rights as everyone else.
Marriage has always been about marriage children were never a prerequisite. In fact the main goal of marriage, early on, was to act as an alliance between families. Our constitution is very keen on liberty and freedom. Marriage was never mentioned in the constitution. I have a fundamental understanding of marriage and it has not led me to the re-definition of marriage it has led me and a growing majority of society to understand that all of us should have equal access to it's blessings.