Property rights aren't "useful and important." Property rights are the fundamental basis for any other right. What right to life does anyone have if not because they "own" their own life? What right to free speech do they have if they do not "own" their own speech?
Thievery doesn't become acceptable because someone makes a compelling case or a pretty argument. Justice doesn't become "fundamentalism" because it won't compromise with injustice.
That you have found a way to construct all the rights you can think of based on a specific construction chattel property rights is interesting. But it doesn't it make it the only way to think about rights (or ethics or morals), or even a particularly good one.
Your fixation on one thing and your refusal to compromise or even to admit the validity of other views is exactly what fundamentalists do.
I was absolutely serious about that comment. Am I being downvoted because people disagree, or just because the Libertarians here don't like being told that treating lives as property ownership is the basis for slavery? Either way, I'm open to discussion on this point.
Thievery doesn't become acceptable because someone makes a compelling case or a pretty argument. Justice doesn't become "fundamentalism" because it won't compromise with injustice.