Harry, you lightly touched upon the key issue here. Who benefits from "gay marriage"? Follow the money.
Back in '95, if you asked the gay community what their biggest issues were, you would not have gotten the ability to marry. Wouldn't have even shown up on the list.
Since then, however, the divorce attorneys recognized that there was a whole untapped market waiting to be fleeced- er, serviced.
A brilliant marketing move ensued to cast marriage (as opposed to civil unions) as a civil rights issue. It took on a life of its own.
Just think, what contract is so easy and cheap to get into, that is so difficult and expensive to get out of?