Fix on? Fixated?
Mentioned once. But, OK.
You, though, are quite obsessed with your white whale of positivism. As someone who lacks the rigidity of philosophical thought to be such an adherent, and who has made no assertions here holding me in that camp, I suggest that you find someone else on whom to fixate.
What concerns me more than this spiritualism of natural rights is the strength of our legal rights. I'm happy that there are multiple ways to convince folks to preserve and strengthen them, whether it is by an appeal to God, an emotional appeal to something innate in carbon based life, an appeal to the utility of the happiness they bring to many, or an appeal to the pocketbook if that is what it takes.
What good is a natural right or natural law if the default setting for humanity is to violate them with impunity? History tells us that violating every natural right anyone has concocted is just about our favorite pastime.