Your statements include so many assumptions.

Why do we worry about national border in the first place, and why do they need to be guarded in the first place? They are not analogous to private property lines. Why does my rejection of your initial assertion lead to justification for a national border enforcement system? It does not follow.

I am a philosophical anarchist because I reject these presumptions behind national so ereignty and political authority. They do not withstand scrutiny. Why do you assume the goodwill and virtue of the political class? Government now invades our lives, liberty, and property while its centralized power draws the corrupt like moths to a flame. An expropriating property protector is self-contradiction. I trust strangers more than I trust bureaucrats.

Just look at Ukraine and Russia. Those government borders engendered a needless conflict, and the political squabbles of the governments have led to untold destruction and death. People use the term "anarchy" as a bogeyman, but apologists for government are the ones with the burden of proof to justify bloodshed and chaos.