Gay marriage is not just an abstract question. We’re talking about the lives of real gay people, their equality and dignity, and their right to flourish openly as who they are.
Are you in solidarity with gay people’s assertions of equality, dignity, autonomy, and marriage equality or not? It’s as much an existential question as a procedural and inside baseball question for this or that religious or political institution.
In the 1960s, it wouldn’t have been reasonable to discuss the inside baseball of the black civil rights movement and the women’s equality movement without expecting someone to raise the issue, if you opposed them, of your own justification for doing so. You wouldn’t get the luxury to just game the state of play. By your very resistance to the full equality and dignity of others, you wouldn’t have earned that. You couldn’t have expected that.
It’s the same today.
The very pressing of the issue of gay marriage by gay people insists on justification from those who oppose them and support the status quo.
Gays have experienced millenia of discrimination, violence, and closeting, and we are now living at a moment in history in which gays are asserting their equality and declaring that their essence and inclinations are neither evil nor disordered. If you say that they are, that needs justification.