So the argument is that people who argue against property rights are inconsistent, because they exercise self-ownership while speaking. The underlying generalized argument seems to be this:
1. You perform behavior X that fits into category A.
2. So you agree that we should approve behavior X that fits into category A.
3. So you should also approve behavior Y and Z that fit into category A.
But this is not valid in general. This reasoning is only valid to the degree in which the behaviors in category A are homogeneous, without significant differences. In other words, by employing this reasoning, one assumes that category A is the overriding principle that should settle the matter, although this is probably one of the main points of dispute. If this type of reasoning would be valid in general, then, by carefully choosing categories, one could “prove” that almost any behavior is acceptable (or not acceptable), for example: Suppose a stranger on the street asks you a question without invitation. This means he is sending sound waves that move your ear drums. This fits into the category: moving a body part of someone else without permission. So this means he should also accept any behavior where someone moves a body part of someone else without permission. But of course, this claim is absurd and invalid, which illustrates the point.
Because without you there would be no chair, in the same way that if you punch me, you 'own' that action because without you, there would be no punch. You own that which you 'cause' or create.
Humans cannot create something out of nothing. Without the chair maker, there would be wood available to make another type of furniture. Humans can only manipulate objects into a different state or configuration. People have different opinions about the value of configurations of matter, and in some cases (an example is given below), even libertarians are not willing to grant ownership to those who have caused a new configuration of matter.
By that definition of ownership, the wind 'owns' the leaves of a tree which is pushes about. Surely you can see how I'm finding a gap between that understanding and the capitalist's property paradigm?
You are making valid points, but I think the example of the wind that moves tree leaves is problematic, because wind is not a voluntary actor. It might be more instructive to take the example of someone who walks on the beech and creates footprints in the sand. The impressions in the sand are the results of his actions, but it is generally not accepted that he will own the land because of it.
Although I agree to a significant degree with the libertarian view of property rights, I think the cause is not advanced by claiming that something proofs it, when it in fact, it does not.