Webdevs: is there a reason why a page would be designed so that JS being on is mandatory? Especially for something as prosaic as a couple of paragraphs of text.
If you meant mandatory in terms of the actual medium requiring it, I can only hint to interactive applications, aside from that I don't think it would actually be mandatory.
Gatsby + Netlify with a CMS-as-a-service like Contentful or Prismic will lead you to a good result. We made e.g. https://fox-it.com/ using that, its back-end is Wordpress but it's drained empty to rebuild the website. Note how it works without JS, the dropdowns don't work but they fall back to full page navigation page. Note how with JS enabled, all the content shows up instantly. This is how it's supposed to be done.
Here's an idea: add some HN logic to automatically move a comment that begins with "TL;DR" to the top of the thread.
I think in the case of Google, it's because they've been told they are the best developers, the top 1% of SWE's, they went through rigorous interviews, are paid a small fortune twice as much as they would get at a regular coding job, etc.
So it's dick shaking. They need to show to the world that they're better than plain HTML websites, that they have a massive schlong, that they out-chadded the vast majority of software devs. Plain html? Psht, we can invent our own language, gonna put those six years of uni to work! Wordpress? This is beneath us! It has to be a client-side rendered JS-pulled-through-GWT behemoth because on my system it's... wait it's slower, but nevermind that it's technologically ALPHA.
edit: actually looked at the source, looks like a Polymer / Web Components website. I've had to work in that once, it was dreadful compared to libraries used by real people.