Well, Enlightenment ideals that were still based in semi-religious terminology aside, "their Creator" does not necessarily require an appeal to the supernatural.
One would, I think, be justified interpreting that to mean the physical processes of the Universe from which humankind arose (justified in interpreting the meaning of 'their Creator', not necessarily possessed of an easily established and defended position regarding how rights themselves rose from the primordial soup (which I must admit would make for an entertaining read)). Science had yet to provide an explanation for the origin of life, as I'm sure you know, and we can safely dispense with the defense that these rights come from a god. To suggest they come from the Universe is equally silly, but it's a hell of a lot better than the supernatural.
One would, I think, be more justified interpreting it properly just as you said--the Creator is humankind itself, like everything else in society. All (nearly all?) notable political theorists have built their analyses of social states on the premise that there are fundamental rights agreed to be important for all persons, for which humankind organizes governments/societies to protect and guarantee in the pursuit of justice. (I can't think of a notable theorist who has argued otherwise, but would be interested in knowing of one.)
Their appeals to the supernatural aside, the founders are certainly the creators of the rights of which we still believe we are endowed.
One would, I think, be justified interpreting that to mean the physical processes of the Universe from which humankind arose (justified in interpreting the meaning of 'their Creator', not necessarily possessed of an easily established and defended position regarding how rights themselves rose from the primordial soup (which I must admit would make for an entertaining read)). Science had yet to provide an explanation for the origin of life, as I'm sure you know, and we can safely dispense with the defense that these rights come from a god. To suggest they come from the Universe is equally silly, but it's a hell of a lot better than the supernatural.
One would, I think, be more justified interpreting it properly just as you said--the Creator is humankind itself, like everything else in society. All (nearly all?) notable political theorists have built their analyses of social states on the premise that there are fundamental rights agreed to be important for all persons, for which humankind organizes governments/societies to protect and guarantee in the pursuit of justice. (I can't think of a notable theorist who has argued otherwise, but would be interested in knowing of one.)
Their appeals to the supernatural aside, the founders are certainly the creators of the rights of which we still believe we are endowed.