Aren't you studying law? It's not that sanctity has no meaning to me. It has meaning, when it comes to religious ceremonies and such. What I'm saying (very clearly, I might add) is that it has no meaning in terms of legal contracts. That's not a "to me" or "to you" thing. It's an objective fact that it holds no meaning in the case of legal contracts.
And yes, there is a reason it should not influence his vote. Because it has nothing to do with a legal contract. The vote isn't about religious marriage, where the idea of sanctity is relevant. It's about a legal contract that has nothing to do with holiness or sanctity. This is the biggest problem with the issue, that religious people ignorantly believe legal marriage is the same thing or similar to their religious ceremony. That's just plain false.