Earlier quoted context omitted.
There's a difference between legal rights and natural / human rights. The latter are ideals, the former are what are brought into existence by the application of force. Intellectual property corresponds (somewhat poorly) to the natural right of being allowed to profit from your ideas.
There is no natural right to profit from your ideas. Your ability to even try to profit from your ideas is substantially dependent on external factors in your life -- your position in society, your ancestry, the availability of capital and your ability to acquire it, etc. Do not confuse the right to think with the right to profit from your ideas. You do have a natural right to think about whatever you want, as well a…
But sure, I don't believe in absolute natural rights, much as I don't believe in absolute morals.
Put more simply, I believe that authorship is a natural right, just like ownership. You might ask, why should the idea be mine just because I got to first? And I would answer, why should the tree be yours just because you got to it first?