“He also stated that religious beliefs should not be given greater weight in political matters than mathematics or science (this means that religious beliefs should also not be given less weight either).”

He did not state this. He said “that our civil rights have no dependence on our religious opinions any more than our opinions in physics or geometry”

Very clearly he defined “our civil rights”, not all political matters as you alluded to. As you already agreed our government is secular, but the people are not. Political matters should be secular, and staying completely out of religious topics in order to protect the freedom for all people to practice religion in any way they want.

@Euripides, If Marriage is a religious institution that must be respected, it never should have entangled itself in our government system in the first place. It’s existence in laws is clearly going against this ideology as described in this post. Otherwise those people who do not hold the same religious beliefs as you do are being discriminated against by the government, and prevented from practicing their religion as they see fit.
There are two solutions:
1. Ban any marriage restrictions or requirements from all laws in the country.
2. Accept that marriage is a social institution and legal status, and not only a religious institution. Hence opening it up to people of all religious beliefs.

Thanks