Brutalism is, of course, a fuzzy (and contentious) label to begin with. But the article cites two interpretations of the term that we could use to evaluate how Brutalist a given design is:
honest, unpretentious and anti-bourgeois
and
a sense of roughness, exposed structures and visible thought processes
The problem is, I'm not seeing a lot of either of these in the examples provided.
If you asked me to name a site whose design is "honest, unpretentious and anti-bourgeois," for instance, examples that would leap to my mind are Craigslist and HN -- both of which focus on simple (even drab) layouts dominated by plain old text. But the examples are full of vibrant colors, big images and irregular, unconventional layouts! They're refreshing and interesting to look at, but that doesn't make them Brutalist.
And to the other definition, "exposed structures and visible thought processes," I'd point to... well, I'm not sure what I'd point to. I'm not sure there is any web site that would qualify as Brutalist by this definition. Are there any sites that let their plumbing hang conspicuously out on the sides? Bloomberg and Dropbox and the Outline certainly don't. I'd think of this more as a site where you interact with it via an API or the developer console or some heavy, overwhelming user interface than as a news site that happens to have decided to use giant fonts and screaming neon colors.
If we want to have Brutalism as a valid design approach for the web, we first need to decide on what exactly the word means. Otherwise it will just become a parking lot for whatever trends happen to be fashionable at the moment, which is not a great way to build something that will make a lasting impact.