I have lots of gay friends on Facebook and those who vehemently support them. Their primary reason for supporting gay marriage is that they hate the dogmatic intolerance of the religious right trying to dictate to them how they should live and what they should believe. In their attempt to sway us away from our beliefs and doctrines for its intolerance, they often display the most hateful,vicious intolerance themselves for those with whom they disagree. The hypocrisy is lost on them. Do not trouble yourself to respond.
For that type, I think mocking them for wanting to become straights would make them think, those sound like the type that used to be proud of being dogs, debauchery loving outsiders, freaks, now they think they want to be like old monogamous straights.