Following are his statements, with my responses.
1) Because people value so-called "IP," property rights are necessary in so-called "IP."
Intangible goods are scarce and rivalrous
People value intangible goods, just as they value physical goods. Just as with physical goods, property rights to intangible goods are necessary because they are scarce and rivalrous.
Briefly, an intellectual work, like a song, is like a factory. At first the song does not exist. Once homesteaded into existence, the producer of the song owns its productive capacity, just as one can build and own a factory. Making copies of a song is like making copies of a widget on the assembly line. The song owner is entitled to 100% of the productive capacity of the song, just as the factory owner is entitled to 100% of the productive capacity of the assembly line.
A person will use their property in a way that brings value. Valuation is subjective. Thus, "use" is subjective. The producer's use of a song is to exploit it commercially, thus unauthorized copying interferes with the producer's use. Only by presuming that valuation is objective can one decide that copying does not interfere.
Much of Intellectual Space is devoted to an explanation of this concept. In particular, see "Grammy Essay", and "The Alleged Case Against Intellectual Property".
2) Contracts involving so-called "IP" are impossible without assigning property rights in so-called "IP."
No property, no contract
That is exactly correct, contracts involving IP are impossible without assigning property rights in IP. Please see Rothbard (and indeed Kinsella) on the title-transfer theory of contract. One may only contract with that which is one's own property. If there is no property right in a pattern of ideas, then one cannot buy, sell or license that pattern of ideas.
3) People would only be ostracized if they violated someone's property right.
No property, no wrong
We do not ostracize randomly. We ostracize those who have done something wrong. If there is no property right violation in, say plagiarism, then it is not wrong. Thus, without IP, there is no basis to ostracize.
All legal rights are property rights. Period. All legal wrongs are property violations. Period.
4) People necessarily have property rights in the products of their labor.
Service contracts are title-transfers
A person rightly owns the product of his labor, assuming he did not violate the property rights of others in the process. Keeping this in mind helps clarify why a service contract is a contract for the exchange of property titles, just as with any contract.
Suppose you hire me to paint your house. I am renting my physical body to you for some period of time, which I may do because I own my body. You agree to allow me in while I work, which you may do because you own the house. I agree to let you keep the layer of paint on your wall, which is the product of my labor.