I define an authoritarian as someone who asks: "Have the people been granted this right?" I define a libertarian as someone who asks: "Has the government been granted this power?"
You know who you are.
That's neatly said, IMO. The Constitution does not list the rights of the people, it enumerates the limited powers of the govenment. The people retain all natural rights, with which they were born, "endowed by their Creator."
This in no way means that true advocates of liberty are contemptuous of ethics and morality - the people must, on a local level, for the survival of society, write laws and codes of conduct, usually based on Judaeo Christian values. Generally such laws and codes must be concerned primarily with prohibiting citizens from interfering with the life, liberty and property of other citizens and to a far lesser extent with traditional customs which have come to be accepted as necessary for society's preservation. Other than actions specifically prohibited by such codes, it is and was understood that the people retain all other rights.
It is specifically the authoritarian viewpoint (in the case of socialism, derived from rationalism), which imagines that the peoples' rights are granted by a higher authority, and that it is up to that authority to create a limited list of specific rights for the people, along with a list of reasons they may supply for the justification of the exercise of those rights.