I agree.
Something happened to some friends of mine a few years ago that really crystallized what same-sex marriage is all about. They aren't a same-sex couple themselves, but the incident demonstrated the real value of marriage to me:
My friend, who's had asthma his whole life, but didn't realize it was as bad as it was, went into severe respiratory distress one night. He was rushed to the hospital and put into an induced coma. He did make a full recovery eventually, but he was unconscious for a month, and awake but intubated, drugged and generally out of commission for another month after that.
Meanwhile, though, his wife still had to attend to all the normal things that a person has to do, like pay the rent and the utilities. However, she had a problem: his salary got directly deposited to his account, and she couldn't pay the mortgage without it.
As it happens, because they were married, she was able to go into the bank, explain things to the manager, get access to his account without much trouble, pay the mortgage, and get back to the business of helping her husband recover and caring for their children.
It was then that I realized that when a person says "I'm against same-sex marriage", they're effectively saying that if a same-sex couple was in a similar situation, the best outcome is the one where the person's partner and young children have their mortgage foreclosed and get thrown out into the street.
I think this is monstrous, frankly. I sincerely hope that people who are opposed to same-sex marriage are opposed to it because they haven't thought things through, and not because they really are so vindictive and, IMO, evil that they would wish this on someone.
The rights of marriage matter most when things are at their worst. Denying the rights of marriage to same-sex couples really just amounts to kicking people when they're down.