Tl;dr: we ought to take note that this is not libertarianism or conservatism, the authors are just using libertarian concepts to make good old progressivism more coherent and effective. I'm totally fine with it :)

It is a libertarian approach to doing progressivism. Those have been tried in the past, most notably much of the progressivism in the first half of the 19th century was libertarian in approach, but I would argue they have been systematically underused at least in the 20th century.

Not that I'm a dirty prog mind you. (~_^)