Please enlighten us regarding the rights that they do not have.
Don't get me wrong. They have
those rights because they are humans. The government just doesn't protect those rights in many cases. Here's what I mean:
The Supreme Court has opined no fewer than 14 times that marriage is a basic human right that is protected by the Constitution. When two people consent to make a life commitment to each other for whatever reason, they each have personal rights and interests in that commitment, be it property, children, or whatever else exists within the institution of marriage as well as the personal relationship between the two parties. Being that these two people have rights within an agreement they've made with each other (be it religious, secular, or both), the government's job is, of course, to protect those rights. That's why the government is "in the marriage business" in the first place--to protect marriage rights.
If two people of the same sex consent to a life commitment to each other, be it religious or secular or both, and if they want to call this agreement a marriage--by the way, I know no one on this site who disagrees with a couple's collective personal right to do this--then they are married to each other if they say so. Being that marriages of this nature may include situations of property, children in legal custody, etc, these marriage rights must be protected by our government. That's what government does--protects rights.
Our government does not unequivocally protect these rights, and not only it is a direct violation of due process rights as enumerated in the 14th Amendment, but is a violation of their basic human marriage rights as well.
They have the right to marry each other by virtue of being human and having the ability to consent to a marriage. Our government must protect those rights.