@neologist,
You asked why civili unions are not acceptable. They are not acceptable because they are being provided benefits for nothing. Why do we provide benefits? Do we just give married couples money because we like to give away our money? Of course not, the reason a society gives a subsidy is because they are attempting to promote a behavior that is more valuable to society than the money society is paying out to promote the behavior. There is only ONE behavior that provides enough of a benefit to make up for what couples take out in marriage benefits.
I pointed this out earlier... Lets take two couples. We will call them Hetero Couple and Homo Couple. BOTH couples will take more out of the system in the form of marriage benefits than they put into the system to help pay for those benefits. To make the numbers easy to understand... Lets say BOTH couples take out $200,000 in marriage benefits and they both put in $100,000 in taxes. That means BOTH Hetero and Homo couple are net negative $100,000. The difference is that Homo couple is incapable of reproduction in and of themselves. So when they die their revenue stream ends as being net negative. Now Hetero couple is net neg $100,000 as well however they produced 4 children. Two of those children got married and two did not. The two that did not get married pay $50,000 into the system making up for the $100,000 that their parents were in the whole. The other two children get married and have more children and so on and so forth. That revenue stream that was created by the heterosexuals could theoretically be worth trillions of dollars to society and last for thousands of years. THAT is why we provide benefits.
Homosexuals simply do not qualify to receive those benefits because they do not provide the behavior that we're paying for.
I also pointed out that by making them civil unoins, you provide them with the right to adopt children.... and I've alrady pointed out the grossly disturbing statistics of pedophilia in the homosexual community.