Now this is not to the point of the OP. But isn't some group always trying impose some standard or morality on the rest in democracy? Surely, no civilization can survive without a standard of morality- and I don't think at any time there will be a total consensus on every issue.
I am for the separation of Church and State- but not of law and morality (certainly at least, not a total separation). In certain spheres, freedom prevails as a value over legislating morality- but not in all.
There is no doubt that society must enforce some type of moral code - and it uses its laws to do so. No one questions that murdering another person is wrong, so consequently, that particular action is considered immoral and illegal. Notice that one does not need a religious basis to come to the conclusion that murder is wrong, or that it should be illegal.
Conversely, society does not outlaw the overconsumption of sugars, which, although harmful to the individual, does not rise to the same level as murder.
The reason for the discrepancy is that, in the case of murder, the state has a very clear interest. In the instance of overconsumption of sugars, the state has no real compelling interest.
In the instance of same sex marriage, I see absolutely no compelling interest for the government - do you? What happens in someone's bedroom, between consenting adults, is of absolutely no interest to the state.