Well... Yes. But at the same time, it is important that positive freedoms are granted either equally, or by some system that fairly judges an individual's worthiness of this freedom. For example, the state grants you a driver's license (a legal symbol of your positive right to drive), only if you can pass a test proving that you can be trusted behind the wheel. They do not deny this right based on race, color, religious grounds, political orientation, or for that matter, sexual orientation. All that matters is that you can drive well.
A marriage license should be granted in much the same way. It shouldn't matter if you are black or white, a good practicing Christian or a Pagan, or if you are gay or straight. There could be requirements on it -- proving your love is a bit hard, but there could be a breathalyzer test to keep you from marrying while drunk, a short written exam showing that you know the legal ramifications of a marriage, and perhaps a spoken contract binding the two spouses to care for either other for as long as they both should choose. Of course, we don't require any of that now. Any two idiots who walk into the courthouse can get a marriage license, and getting someone to preform the ceremony is just as easy.
Personally, I think it would be funny, and well justified, to vote that Christians should not be allowed to marry in my state. There are, I know, many who would support such a law, if only because it amuses them. Such a law will never come to vote, because it's just plain stupid. And, in case you haven't guessed where this is going, Proposition 8 was exactly that kind of stupid.