If the public square thought it was a mere piece of paper, the passions evoked on this issue seem very odd indeed. It is more than a piece of paper, much more. It is about recognition in the public square that vows of intimacy among consenting two adults should be given repect even if of the same sex.
So you admit it: the minority is demanding approval from the majority for something the majority finds immoral. If the minority can't persuade the majority to concede on its "backward" and "prejudiced" positions, then it is hoped that the sovereign authority of the courts or the legislatures can be used to enforce this new set of values on the majority.
Don't you see the threat to the consensus of the governed in this strategy?