You can't just use HTML because browsers have mutated to fat clients for a X like protocol which is a mishmash of html, css, js, and whatever else someone's decided to throw on top of it.
We're using screwdrivers as axes and everyone is acting like this is some type of acceptable outcome.
You can't make as rich an interavtive experience as you can with JS, but you never could.
These are some of the JS functions HN runs in the background, on top of the CSS:
function $ (id) { return document.getElementById(id); }
function byClass (el, cl) { return el ? el.getElementsByClassName(cl) : [] }
function byTag (el, tg) { return el ? el.getElementsByTagName(tg) : [] }
function allof (cl) { return byClass(document, cl) }
...I think the parent poster was referring to how much noise there is, and I'd agree. The moment you start learning, just the fanciest stuff is shoved down your throat. So you just assume its the best and roll with it.
I find myself tinkering more with PHP now that I've been using js for the past 7 years.