Who is the driving force behind same-sex marriage?

You can easily predict how any LGBTQ person will answer that question. If that person supports same-sex marriage, that person will say that lesbians are the driving force. If that person doesn't support same-sex marriage, that person will say that gay men are the driving force. Some people will elaborate and blame upper-class white gay men, who, in case you still haven't heard, are the root cause of everything bad that has ever happened.