I have to say that I'm getting tired of this topic. But since the issue is still a live one, we'll keep responding. We received this question and I thought the answer I gave might be useful to others who I suspect hear a similar argument about Prop. 8.
"What this tells us, quite strikingly, is that Proposition 8 was a highly successful effort of a particular religious group to conscript the power of the state to impose their religious beliefs on their fellow citizens, whether or not those citizens share those beliefs. This is a serious threat to a free society committed to the principle of separation of church and state."
He also stated that friends and family that voted "yes" was a message to him - that we don't care enough about you (my gay friend) and your happiness.
Here is my answer:
First, I recommend this article of Greg's from the webpage about the role of religious convictions in voting.
Second, separation of church and state has nothing to do with individual citizens voting their personal views and consciences, whatever those are based on. Every citizen uses the sum of his background, values, and beliefs to vote. There is no requirement of democracy or a free society that requires any voter, including religious ones, to set aside any of their principles in making their vote.
All kinds of laws, in fact most laws, are based on morality. Even if same-sex marriage were legalized, that would also be a moral view. So there's no way to get morality out of this polity policy decision. Every citizen, religious or not, is involving morality in their vote. That's not a vice of religious people only. It's not a vice at all.
I do think that in the public square, Christians should make arguments that appeal to all people not only those based on the Bible. We cannot expect non-religious people to be persuaded by religious arguments. But that doesn't mean Christians should not make up their own minds based on their religious views.
Separation of church and state simply and only limits government from making any confessional and doctrinal requirement of citizens in the form of a state church. Separation of church and state is a limitation on the government, not individual citizens. The Bill of Rights specifically, as a whole, is a limitation of the power of government to protect the individual liberties of citizens, so to try to conscript it to reverse it as a limitation on individual citizens is quite perverse.
Greg mentioned the issue of love in his commentary on the radio show Sunday so I would suggest listening to that. This person should consider that love cares for the well-being and good, not just the happiness, of people. The people who love him who voted against same-sex marriage have true concern for his well-being. And they also have to have in view the well-being of society as a whole, which love would also require. Demanding love to be on his terms is a very selfish viewpoint. Love doesn't concede to demands that in the end might be harmful to the individual and society.