“It comes down to a question of whether property owners have a right to deny access to their land to others, arbitrarily . . .”

No, it does not come down to that at all. I am quite happy to welcome undocumented immigrants onto my property; so what it comes down to is a question of whether or not other people, who do not own my property, have a right to deny access to my land to others, arbitrarily. Of course they do not. They have no right to do anything but keep their preferences, and their borders, on their own property, not on mine.

“This may well be true; but if so it actually renders all argument irrelevant since their right to have any policy- including open borders- unsupportable. For instance, an illegitimate state operating an open borders policy is enacting unjust domain over the properties of its citizens-”

Horsefeathers, sir. This is absurd.

Of course you are right that in my view, no nation-state can legitimately have any policy at all, because no nation-state can legitimately exist. But the mistake here is in trying to treat political demands for amnesty or open borders as if they were demands for an active policy in the first place. They are not demands for government action; they are specifically demands for a structured sort of in-action, and they cannot reasonably be described as “actions of an illegitimate State against its oppressed citizens.” They are not impositions of “unjust domain over the properties of its citizens” because the property rights of a states’ citizens don’t include the right to force immigrants off of other people’s property in the neighborhood. Nothing is being imposed upon them, any more than the absence of war is somehow the political imposition of “peace” on unwilling civilians; or, at least, if you are going to claim that a state without border restrictions “is enacting unjust domain over the properties of its citizens” in virtue of its lack of border restrictions, then you will have to tell me whose property rights are being restricted by the open borders, and how they are being restricted by government’s simple refusal to harass or detain international migrants.