The bottom line is that nation states matter. And while nation states are primarily defined by their ideas and laws, they're also defined by their borders. If you allow completely unregulated and unfettered movement in and out of your country, you defeat the very concept of the nation state. I am a citizen of the United States, not a citizen of the world.
Nation states have the obligation to take good care of their citizens AND the Persons (as in our constitutional definition) who reside within their borders. It says so in the Geneva Conventions and the Law of Nations You haven't shown at all that unfettered movement in and out of the country defeats the concept of the nation state. Not in the least. And I've discussed several regulations that would apply to anyone entering the country: 1) Abide by our criminal laws, can be sued in our courts 2) Pay fees and duties on goods brought in 3) To become naturalized as a citizen, abide by those requirements 4) Pay taxes &c
Freedom and Liberty are great things, but your rights end where your fist reaches another's nose. I don't advocate lawlessness or anarchy - far from it. If someone tries to smuggle in slaves, we should put an end to that. And so on.
You seem to support the lax enforcement of illegal immigrants into this country. That is a form of lawlessness or anarchy in where we just allow people who come here illegally to remain here.
I support the right of people who've been migratory for centuries to continue to do so, among other things. I see this as a free country. People want to come here for the right reasons, of which there are many, who am I to want to pull up the ladder now that I've made it here (4th generation of my family born in the USA)?
You can't selectively enforce lawlessness. If you support the rights for anyone to simply walk across the borders, unchecked and with no repercussions as they get here, I don't see how you can enforce any sort of border and/or customs enforcements. They are intertwined and the rules are there for a reason. You assuming they are coming here for the "right reasons" is just an assumption.