Church stand is just duplicitous
When it comes to the Church and marriage, it shouldn't be forgotten that for the first 1,000 years it had nothing much to say about marriage, while some Christian groups explicitly forbade it.
From a moral point of view, women were regarded much as gay men today, as agents of depravity: carnality would always be trumped by celibacy.
For the Church now to pretend to be the guardian of some higher moral view or natural order is totally duplicitous. Its antagonism to gay marriage reveals the malign mentality still viscerally embedded in its thinking.