[0]: https://developer.mozilla.org/en-US/docs/Web/HTML/Reference/...
You say that JavaScript and fallbacks for menus is a solved issue but the number of menus that are just an absolute clusterfuck is ridiculous on the web today. They're really not a solved issue, Progressive enhancement is hard to do. Genuinely hard in some cases.
On balance, while this is not without flaws, it's interesting. Accessibility, deep linking, reduction in cognitive load for the developer. There's some merit here.
It's, um. Not the best kind of communication, and very easily leads to this kind of misunderstanding.