At the start of the article they do state that you might need javascript. The point was to show off things you can do without javascript, not say that you never need it.

Of course it doesn't undermine it's own credibility. If you turn off JS you'll see that the site still works. It's progressively enhanced using JS to give you examples of what is shown here.

did you accidentally go to site called youshouldneveruseJS.com? Because I think we were talking about you-MIGHT-not-need-JS.

Indeed, a bit funny for a site titled "You Might Not Need JavaScript" to itself use JS.