Libertarianism, like Leninism, is an attractive, internally consistent ideology which provides a prescription for achieving a utopian society populated entirely by frictionless perfectly spherical human beings.
Lenin and his followers tried to achieve their goal by, well, the political equivalent of chopping off all the spiky extrusions and compressing people into vaguely spherical shapes. We’ve seen how well that worked, and most of us said “no thanks”. The trouble with Libertarianism is that because we don’t have a clear, recent historical example of a Libertarian nation built on the same pile-of-skulls methodology, Libertarians can apply the “no true Scotsman” argument when defending their fundamentally broken model of human behaviour. Which is why they’re so tiresome and persistent.
TL:DR; don’t trust ideologues who come bearing attractive theories that over-simplify human behaviour.