One way to tell the intellectual inconsistency of open border libertarians is by watching their reaction when you explicitly disassociate yourself from other people in the same country as you who are not your countrymen or your people in any sensible manner.
Whenever you get into a debate with them about immigration or borders, just say “it doesn’t matter if they come or go or what the government does, they’re not (fill in the blank ethnic group) and never will be. They’re not my people and I refuse to be associated with them on any basis other than the fact that we’re ruled by the same government. Therefore, all appeals to a shared identity between myself and them are invalid.”
Then watch them kvetch and call you all sorts of names for not accepting a coerced collective identity as decreed by your wise state overlords.
Remember, these are the same people who mock collective identity based on race and/or the “imaginary boundaries” of political jurisdictions, but then flip out when you say that certain people in that jurisdiction aren’t your people just because, well, because that’s racist!
By doing so, you’re not advocating government policy or even making a political statement. You’re declaring an identity independent of other peoples you don’t wish to be associated with. You’re declaring yourself separate from other peoples claiming to be one of you because they happen to have set foot on the same dirt your ancestors did.
For heritage Americans such as myself, it’s a one-way street: for them, anyone can become an American – which of course begs the question as to what is an American. I have yet to find a single open borders libertarian article or blog post that makes the case for heritage Americans to reject efforts to force a collective identity with the immigrants entering the country. In other words, none of them are saying, “government borders are wrong, but that doesn’t change the fact that the immigrants coming here aren’t Americans and won’t be, and actual Americans are free to maintain a separate identity in the form of culture, traditions, customs, beliefs, values, and collective historical experience.”
Ironically enough, for people who love to bash nationalism, they actually cherish their own form of it – civic nationalism.
The reason? They’re cosmopolitans who hate, hate, hate, hate the notion of anyone
anywhere of Western descent separating themselves from non-Westerners in any manner and adopting a distinct identity in which there is “us” and “them.”
Ultimately, they’re not anti-state borders; they’re anti-boundary activists, many of which secretly harbor a fondness for the ongoing deconstruction of Western ethnic identities in which Westerners are not allowed to define their identities without the supervision of the state and the input of outsiders.