Sally Ride and a genuine question

So, at the young age of 61 the first woman in space, Sally Ride died.  She was part of my youth and watching her break that barrier was important.  Of course at the time, I didn't know that it was remarkable and that she was doing something no woman had done (or been allowed to do) before.  To me, she was unique because she was on the news.  No one had told me that I couldn't do something because I was a girl.  She was a pioneer and a hero.  She was a champion for education and especially for girls in science. That's a hard sale these days.

Her obituary is causing some ripples because it ends with a simple statement that she leaves behind Tam Soandso, her partner of 27 years. She was GAY and we didn't know it. Gasp.

Some folks are up in arms that she was in the closet and did the gay community a disservice by not outing herself. I totally disagree.

Even though I think our society is served well by knowing that the gay community serves beside us in everything we do, I don't think that everyone who is gay has a responsibility to offer themselves up as a spokesperson.  Ms. Ride's calling was her family and education.  These are honorable causes.  From what I've read it sounds like her family and friends knew she was a lesbian.  That isn't closeted.  Sure, she didn't invite the media and the American people into her bedroom, but she also didn't advocate in the public sphere her stance on lots of issues.

I had a bit of a back and forth on a friends web page on this topic and I gracefully bowed out. I said that I understood where he was coming from but that everyone should have a choice to be vocal or not.  Then I let him have the last word.  After all, he was the one who felt betrayed and I'm just a soon to be middle aged, married lady.

I think our modern American world has lots of progress to make regarding our homosexual neighbors.  I understand that for some folks they may not know anyone who is gay (or don't know they know them) and they have been educated that being homosexual is a sin.  That carries a lot of weight for folks who use sin as a marker for how to live their lives.  Many people are adamant that GOD is calling this a sin.

I don't pretend to know what GOD says or thinks.  We have a nice little book that tells us what some men say GOD said or thought, but many of the items contained within that book are out of date in our modern world and are not followed to the letter by these folks either.  (I've mentioned this before.)  I can only do what in my heart feels like the right thing.

Sorry, I'm on a religious tangent and I wanted to go somewhere else.   My thought process of late has been trying to formulate a question to pose to the world at large about same-gender marriage that goes something like this:

The Washington State law (and upcoming ref 74) regarding same-sex unions does not require any church or religious organization to perform same-sex unions.  Therefore they are allowed to opt out of participating in these unions and can express their beliefs for their congregants anyway they like.

If we take religious arguments, the bible, and God off the table for reasons to oppose same-sex unions, what are the other arguments against it?

I'm interested in hearing a non-religious based answer.  I like religion, I enjoy participating in church and I am not trying to discount that some people feel adamantly that God is against this.  However, we don't limit the rights of others because they don't belong to our church, any church, or heavens to pete don't believe in church at all.   We do inflict Christmas on non-believers but Rudolf is so cute.. you know they like it.

I doubt I'm ever going to change the mind of anyone, but I am interested in hearing a genuine argument that isn't based on religion - especially in a country founded on religious freedom.