As a user, I don't care.

As a disabled user with a screen reader, I might care.

As a developer tasked with maintaining it after the original dev left, I most certainly would care a great deal.

As a developer you maintain the source templates, not the compiled/generated HTML. The HTML is messy doesn't mean the source templates are so.

Semantic web is basically "please think of the crawlers."

Besides the points raised here, I think it's worth noting that using stuff like the article tag does not necessarily make things easier to maintain. You do indeed get a lower line count, but you're coupling the structure and meaning. Sometimes that's fine, but a11y can be tricky to get right and it's often easier to push it off until you've got something working first.

Except that as a developer you have access to the original source code where things are well structured. It only turns into div soup after the React/Vue code gets compiled down to HTML+CSS+JS that can run on any browser.

And it's nearly impossible to customize any part of the layout with user styles because of that.

It's possible to know that HN is basically a big table, use the site just fine, and still recognise that there are disadvantages to that approach.