For context, this article was published by the Cato Institute, a libertarian think tank originally founded by Charles Koch (among others). The fact that these guys are ringing the alarm bell should be a warning unto itself.
https://lp.org/platform-page/ section 3.4 outlines a loose border policy. The US Libertarians may have diverged from most global Libertarian thought, but while shy of open borders, borders aren't something any Libertarian is fond of.
It's not legal in New housing, but removal from old housing isn't required. Though you can use it for other things like insulating kilns or furnaces.