I think one key passage begins on p. 1428 and continues on 1429. Prof. Baron is explaining that since property rights involve legal relations among persons with respect to things, when the law recognizes that X has the right to exclude Y from X's property, then Y has a corresponding duty to X to stay off of X's property. (X's right entails Y's duty).
"Thus, if X and Y were neighbors, each would have rights to keep the other off, and each would have a duty to stay off." (p.1429) Thus, property rights enhance both the liberty and personhood of X and Y, because each has autonomy over his own property (each is the "king of his own castle.")
But what about the person, Z, who own no property?
Prof. Baron says "[p]ersons owning very few things inhabit a realm of severe social and legal vulnerability, susceptible to the power of many...without having (m)any reciprocal power(s) over others." (p. 1427). In other words, "no property" is "a negative, a collection of lacks." (p. 1429)
What are your thoughts? How should the law respond?