I believe they were referring to the fact that JavaScript needs to be enabled to read anything on the site, despite all the content actually being there. It's just hidden by some annoying <div class="mauer-narrator-preloader"><div class="mauer-narrator-spinner"></div></div>.
Maybe you think the spinner is a better experience than getting a glimpse of the partially-loaded page, but I feel like the browser successively displaying content is a much better progress indicator than some dummy image spinning in a circle.