Libertarians who support the Big Government "border security" welfare program don't understand property rights. Property rights are the foundation of all rights, so if you don't understand and support property rights, how can you credibly claim to be libertarian... or to value liberty at all?
"Taxation" is a violation of property rights. If you advocate funding "border security" through "taxation" you advocate violating property rights.
"Eminent domain" is a violation of property rights. If you advocate taking property through "eminent domain" for "border security", so as to place a wall, fence, or other structure on this property against the true owner's wishes, you advocate violating property rights.
If you make up rules which prevent people from employing whomever they choose, trading with whomever they want to trade with, associating with whom they prefer, or renting to whomever they reach an agreement with, you are violating property rights. If you support these kinds of rules you are no friend of property rights. You are just as bad as any other thief or trespasser.
Respect-- or lack thereof-- for property rights doesn't depend on where a person was born. Those most threatening to my property rights have always been home-grown archators. This doesn't mean others can't also be a problem, but to focus on "others" while supporting those who are actually committing the violations right here right now is to miss the point. It looks statist.