Where the Libertarian position on same sex marriage falls apart is that the leftist plan for same sex marriage includes a plan to control religious believe and teaching against homosexuality along with controlling speech, interfering with religious belief, it’s thought control.
I don’t see how that fits into the concept of Libertarianism.
LIbertarianism is merely the ultra kook anarchy hedonism/false utopian fringe of the left. It’s about time people woke up and smelled the methane.