I'm not familiar with that old tale about Zeldman. It's true that assistive technologies don't know about CSS class names but CSS absolutely can affect a non-sighted screen reader user's experience.
I don't use Tailwind so I don't know if it makes it easier or harder to do the right thing when needing to hide something from everyone or only visually hiding something. Because it's CSS, it can't take care of only hiding something from assistive technologies.
The structure of your CSS, and the structure of your divs, do not affect AT experience. This is misinformation.
As mentioned below:
A <div> itself is treated as a generic, transparent box. It doesn't get keyboard focus, and it isn't added to the screen reader's elements list (like headings, links, or landmarks).
Sure. I don't know where you're claiming that misinformation is coming from, it doesn't have anything to do with what I wrote. I was referring to CSS properties that affect the accessibility tree.