There are financial benefits to be had by being married. This is only logical, since families are an investment in our future.
Everyone that gets married creates a burden on their employers, the government, and, indirecly, the taxpayer/consumer. More marriages would burden this sytem.
The logical response would either be higher costs, or less benefits. That would be a tangible cost, especially as marriages become increasingly frivious and common. Another tangible problem: more marriages of the unserious variety would lead to more clogging of our courts. That ain't free.
There are intagible costs, as well. Divorce is already a problem in America. Children being born out of wedlock is a problem. If we weaken the concept of marriage even further, it will not result in more stability. Gay marriage is pushing in the absolute wrong direction.
You immorally advocate denying benefits to gay taxpayers/consumers who are paying to support the system, so your concern for those groups is bogus...