Sorry, maybe I should have phrased this differently: Of course that should be fixed! (I have spent the last half year or so fixing a11y issues on a highly frequented website, mainly thanks to the EU Accessibility Act, so I'm starting to get a feeling for how awful non-accessible websites must be.)
What I meant to say was: The lack of a11y doesn't seem to be a deficiency of the library itself but rather of a hastily written demo application/renderer.
The demo should at least have a noscript tag, to tell me why I can't read the page.