The entire page loads instantly for me on Firefox and Chrome, admittedly on a decently fast connection. I tried using it on Chrome with the 'slow 3g' network speed and with cache disabled - in a few seconds the old page is replaced with a blank white screen, in a few more seconds the red background of the header shows up, and a few seconds later all the text renders at once.

What seems to be happening is that the page waits for the woff2 fonts to be downloaded before allowing the text to render. I recall also reading on HN that Google AMP has an 8 second timeout before it allows the page to be rendered, unless the AMP js scripts are all loaded first (so people who use content blockers effectively have an enforced 8s delay). Both are stupid techniques - sure, a user with good internet (and the web designers) will no longer see a split-second flash of text (on this website) or unstyled HTML (on AMP) before it switches to the new font - but it's effectively a mandatory delay for those who don't have this privilege. An improvement of 1% for the [rich and included] and a significant decrease in functionality for the [poor or excluded].