“One gratifying aspect of our rise to some prominence is that, for the first time in my memory, we, ‘our side,’ had captured a crucial word from the enemy . . . ‘Libertarians’ . . . had long been simply a polite word for left-wing anarchists, that is for anti-private property anarchists, either of the communist or syndicalist variety. But now we had taken it over...”

tl;dr: The right wing co-opted libertarianism for its own ends...