In my home country (Poland) the fight for same-sex marriage rights is now synonymous with fighting for equality and respect for the LGBTQ community. Even though I know that many queer people there don't actually believe in the insitution of marriage itself (and we have the nationwide Catholic indoctrination to thank for that), I'm not surprised they would want to have that option, just like anyone else. Because at the end of the day - and as you wrote in your comment - if you throw all the silly traditional gender roles and stereotypes away marriage is just a celebration of love. And that will always exist, in one form or another.