Illegal immigrants don’t have the right to become a state within a state
We were not merely migrants, but legal arrivals, who were permitted only because it suited the US, Canada, Australia, etc, to augment their labour supply. But we had absolutely no legal or moral right to enter or, if illegally present, no entitlement either to remain or to secure citizenship in any of these lands. The grant of citizenship and the control of sovereign territory are fundamental and vital attributes of any independent state. Virtual non-enforcement of, say, US border controls, or of any other rights, cannot of itself invalidate the rights so laxly defended.
Despite its huge land frontier with Canada and Mexico, the US still has a tiny border patrol, plus a border landscape that facilitates easy transit of people or goods, or bombs or drugs.