On this planet, humans have read HTML without parsing for years. People building their first websites without any significant technical knowledge stole HTML by reading the source of other sites and edited it by hand.
Oh, please. Don't insult everyone here by pretending you actually believe HTML is a human readable format like markdown. It was never designed for that and has never claimed that.
It is. Humans do read it, and have read it. Like any language it's just a matter of familiarity.
HTML was designed for humans to read and write long before Claude or compiling everything from typescript or whatever, when websites were all written by hand. In text editors. Even if you were using PHP and templates or CGI you wrote that shit by hand, which meant you had to be able to read it and understand it. Even if you were using Dreamweaver, you had to know how to read and write HTML at some point. WYSIWYG only gets you so far.
Is HTML more difficult to read than Markdown? Sure. It is impossible? Not even remotely. Teenagers did it putting together their Geocities websites.
You can be as snarky as you like, but facts are facts.
I don't think they were appreciating that HTML could be read unrendered. I think they meant that it was up to the browser to render HTML with sensible but unspecified or otherwise user-specified styling (the browser is supposed to be a "user agent", remember?) before web designers started aiming for pixel-perfect control through CSS.
HTML markup is pretty readable (except when it becomes soup) and I read and write raw HTML documents all the time. I like it better than markdown.
It's even more readable in a code editor that distiguishes tags from content.