It's actually worse than you're saying.
NoSQL databases have been around since the 60s [1], and the term was created in 1998. Two decades ago. Is the author of this manifesto saying that they'll only work with tech from the 50s? Or is the 80s good enough? The 90s clearly isn't.
In fact, Ajax has _also_ been around for two decades; 1998 was a big year for the web, apparently. The Outlook Web App (a major milestone in SPAs) was created in 2000, 18 years ago.
This "manifesto" is nothing more than "I choose to bury my head in the sand and use outdated tech and ignore the state of the art!"