That is a libertarian goal, totally open borders, and you left out other libertarian victories like homosexual equality and marriage in the military and in immigration and federal employment.
Discrimination in federal employment for any reason whatsoever other than citizenship and ability to do the job is theft from the taxpayers.
I really do not care to whom or what or why you attribute refusal to enforce the borders. It could be Socialists looking for voter base. It could be Libertarians to free up labor exchange. It could be “crapitalists” impoverishing the middle class. It could be equalitarianism, courageous conservatism, whatever.
As your yard is defined by its border, so is our country. Border enforcement is a basic governmental duty that our federal government is NOT doing.
Rulings promoting the homosexual lifestyle in the military were done exclusively during Democrat administrations and by bureaucratic fiat within the military, and NONE of them were rolled back during supposedly socially conservative GOP administrations. I don’t think the Libertarian Party per se had much to do with it.