And again, I reiterate what I said earlier. Where do rights come from?
You're missing the whole point of what the founding fathers and the US constitution was attempting to create.
These inalienable rights "come from" nowhere. They exist innately and the constitution was written largely to express this, and to prevent laws from being created which would stifle or try to remove them. The social construct aspect applies insofar as to how to balance things when the desires or actions of one person impact the rights of another person. They certainly don't come from a god.
Even the creation of the Bill of Rights (first 10 amendments to the Constitution) was criticized by several high-profile people of the time because they were concerned that it would be interpreted as a "list of rights", and if a specific right wasn't in that list, then the People didn't have that right. A concession was the Ninth Amendment:
The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.
One of the dissenters of the Bill of Rights was Hamilton, who said, among other things:
It has been several times truly remarked, that bills of rights are in their origin, stipulations between kings and their subjects, abridgments of prerogative in favor of privilege, reservations of rights not surrendered to the prince. [...] Here, in strictness, the people surrender nothing, and as they retain every thing, they have no need of particular reservations.
One of the biggest differences between the newly created United States versus other old-world countries was this very thing. The recognition that all people have innate and inalienable rights, not bestowed by society or god or privilege or bloodline, but simply because they are a living, thinking human being.
High ideals, perhaps, and we slipped badly sometimes (slavery probably being the biggest), but every time I see people say things "gay marriage isn't listed in the Constitution" I cringe because they have such a fundamental misunderstanding of the country they live in.