The majority of people against redefining the word marriage to include same sex unions, aren't against it because they want to deny anyone any rights.
Waitress - a woman who waits on people
Marriage - The union of one man and one woman
Either both words are sexist and discriminatory, or neither is, or you do not accept the common meaning of the word 'marriage'.As Stephen Fry said, give them all the same rights, just call it something else. "Civil Union" or something.