No CSS is better than bad CSS
In my browser that "Page Contents" box is hovering above the end of the line, so I can't read the full text. Kind of ironic, that this is on w3.org
replies(2):
That's only true if the markup and JS are also good. If, for sake of argument, the HTML had been badly authored such that the links in that menu were DIVs with click event handlers, rather than real links, then removing CSS would likely make the experience worse rather than better.
I guess that a key point underpinning your comment is that progressive enhancement is still better than assuming all potential users are on the bleeding edge, despite the evergreen update pattern for the most popular 3 or 4 browsers.