Total personal opinion:
Yes, actually, reading porn is a human right.
Brought to you by a librarian-by-education-and-public-record
This does not mean I will not protect myself or think others shouldn't protect themselves by asking people who aren't supposed to be reading my fic, to not read my fic. It does not mean that I would interfere in a parent's right to not allow their child to read something.
It does mean that I disagree with their choice, philosophically.
Not so personal, more debateable (ie, actually willing to debate it) opinion:
The internet is not analogous to harmonyfb's refrigerator. Internet NC-17 archive, if un-passworded = unattended booth in the town square with sign that says "Free beer for adults only, from Writer X." If I grant the beer analogy at all, which I don't, because written porn ≠ beer. Because unlike alcoholic beverages, written porn is not illegal for minors in the US to consume. It's only -- possibly, depending on locality -- illegal for an adult to provide access to it.