You’ll probably get to it anyway, but my usual note along the “debunking” like pertaining specifically to CSS is that pixels in CSS are not defined as hardware or device pixels. It’s actually something defined via perception.
I like the irony that at the top of the post is an assertion that it’s exactly 32.36cm long.
That aside, this article is really shallow. “Different screens have different pixel densities!” has been a thing forever, and is about much more than just fonts. (The earliest Macs did have 72dpi, but that stopped being true ages ago.)