WHY does the non-aggression principle apply? And why is intellectual work supposedly not protected by this principle?
Because murder is a form of aggression and copying information isn't.
Why isn't copying the work of someone else against their will not a form of aggression, whereas a threat (which is also just information) while pointing a gun peacefully at you IS a form of aggression?
WHY do you own yourself?
I have the best claim to my body. Everyone else is a latecomer with respect to me and my body.
That's not true. The atoms in your body has probably been claimed hundreds of times by other people, not to mention your parents. They produced you and fed you. Why don't they own you and can sell you as a slave if they like?
Here you are explicitly denying the existence of information
No, I'm not. I'm denying that it's a form of property.
Why?
If you write in a book you own, you still own the book and the writings, the physical copy itself, not the information contained therein.
Why not?