I think there's something to be said for that argument.Why shouldn't they be able to give them to anybody they choose? A sibling? A parent? A cousin? A friend?
Why should someone's right to collect money they are owed be limited to a person they can legally marry, regardless of gender?
but some form of marriage/civil unions has a place when you're talking about child custody, an unexpected death, medical emergencies, or a combination of them (eg: a woman's wife dies while giving birth and the child is in critical condition... if it were a straight couple, the father would automatically have a legal right to decide on the child's medical care and have custody after the fact. without the legal protections of marriage, the woman's family could sweep in and claim custody and they'd be locked in court for months... for the sake of argument, in both cases let's assume the woman was artificially inseminated by an anonymous sperm donor)
it's probably not reasonable to expect gay people to have to jump through hoops where a straight couple would get all that resolved simply by signing on a line.