I was referring specifically to the author's claim that deprecating HTTP and displaying a warning to users is the equivalent of "rendering large parts of the web inaccessible" and "massive book burning".
A lot of content that exists on the unmaintained web is going to effectively be lost, and maybe that's okay because the benefits are worth it, but that's the argument that needs to be made.
It certainly does matter. There's a fundamental different between people being discouraged from accessing a website, and said website being completely inaccessible.
A migration of newer websites to HTTPS is no more a loss to data than deprecating old versions of HTML in newer versions of Chrome or upgrading newer servers to HTTP/2. The old ones will still exist. And if they cease to exist, it's almost certainly not going to be because a browser displays a "not secure" warning on the top left corner of the scene.
There are also entire websites and communities built upon the archival of data: