Freehold, a short documentary that won an Oscar this year, deals with a lesbian detective who is dying of cancer and wants to transfer her pension to her live-in lover. The local authorities turn her down.
The comparison, of course, is to married couples, and the situation is supposed to be a patent injustice perpetrated against sympathetic victims. Mockery and cat-calls won't be enough to respond to the issue.
There's no substitute for having something to say. In particular, conservatives have to be able to say what is so special about marriage and the family that makes them worthy of social support other arrangements don't get. In fact, they have to be able to say what's wrong with same-sex connections, and why it's bad to give any sort of recognition to them. There's a long road back before they'll be able to do that, though.
I suppose there are other more neutral points that could be raised:
Those may be OK as wonkish debater's points, but they're not likely to get anywhere with normal people. The first one in particular may be a good point, at least when made against "progressives," but it probably isn't one a social conservative would want to raise.