This is a rather limited reading of the SF cannon. It's dismissal of Heinlein's late-in-life turn towards conservatism and fascism annoying when compared to its glossing over of the contribution of Ursula Le Guin and the idea that dystopian fiction is by its nature libertarian is an easy to challenge claim. This is especially true in the challenge of parsing cyberpunk which might handle Bad Governments but does not always, or even frequently, adhere to libertarian ideology, especially in the framework of whole authors' work.
Even weirder in this post is the instance that The Illuminatus! Trilogy is some paean to libertarian concepts when Shea and especially Wilson have made it clear that it is instead a mockery of those concepts, much along the lines of... say Bioshock, a solid and popular piece of anti-libertarian dystopian fiction if ever there was one.
It's also worth noting how lacking the impact of the Star Trekian generation of SF, which is very very socialist in its sensibilities, a 60s selection of SF that includes a wide swath of authors and high level of cultural influence.
Unmentioned in this shallow scoop of the genre, for example, is Asimov's Foundation series, which plays across the whole spectrum of politics, mostly looking at negatives and positives in all of the approaches. Or E.E. Smith's Lensman series which was highly influential in its time, and continues to echo in today's fiction, and is fundamentally an enshrinement of the concept of the Government as Parent, indeed in modern eyes almost to an uncomfortable degree.
I find this lacks the rigor to even examine the author's own bias shading their choices and interpretation. It fails to prove out its thesis and it lacks the holistic nature I'd want to see in something that claims to be a "history".
The Lensman series is pretty painful in many ways, it's been over 40 years since I've read the books, and I still remember that the books had a very old-fashioned view of women, even by my teenager in the '70s viewpoint. I remember the writing is pretty bad too. Still, they were very influential, and perhaps I should read them again.
Yeah, the Lensman series is definitely of its time, including some rather gross sexism, but the writing and the stories and how it approached its characters (the hyper competent types) still had a huge impact. I wouldn't bother reading them if you are looking for entertainment, they fail badly through a modern lens. The writing style is particularly unique to that period and while fine in context comes off terribly today, as do (as you note) how it handles women. But if you're interested in the history of SF, it def is a part of that, for better or for worse.
Very good observations. When I saw SF and libertarianism, my very first thought was Robert Heinlein, then other authors mentioned in the article.
"The individual is foolish, but the species is wise."
Au contraire, says SF.