Nobody is trying to convince you to build a chess app that doesn't use JavaScript.
More importantly, Alex is not arguing for you not to build things with JavaScript either!
He's arguing against writing inefficient JavaScript where you ship MBs of code to the browser to serve simple functionality.
Scroll to the footnotes and you'll find a big list of JavaScript frameworks which Alex does recommend, because they optimize for performance and low overhead.
More importantly, Alex is not arguing for you not to build things with JavaScript either!
He's arguing against writing inefficient JavaScript where you ship MBs of code to the browser to serve simple functionality.
Scroll to the footnotes and you'll find a big list of JavaScript frameworks which Alex does recommend, because they optimize for performance and low overhead.