I don't know. Still, at a time like this I would expect a 99% static public website to be up, running and serving all comers. This is a complete mission fail, both in terms of using PHP and in terms of not having a fall-back plan in place.
Due respect, neither of those make sense. PHP is boring software, and this website routinely suggests (1) use it if it is fit for purpose and (2) don't rewrite for the sake of it. For most sites, the engineering effort to have a static backup of their dynamic website (say, generated by Wordpress or Drupal) just isn't possible. They just need to power down and patch.
[EDIT: I see I may have erroneously extended your criticism to sites other than NCSC, for which it does make sense. I would still defend using PHP.]
Because websites with news, continuously updated advice, job openings, etc aren't all that static? This type of site hugely benefits from having a easily understandable CMS that you can teach to more or less everyone in 2 days or less. I suffered through a few of those back in my time in the military, where an instructor would teach a class of 20-30 how to build new pages in the CMS
Now are there more powerful tools out there that result in more scalable websites? Sure. My personal sites are built around static site generators for that exact reason. But none of better tools are as easy to understand for non-programmers as wordpress or one of the other click-and-drag CMS tools.
