it's a bit exaggerated, but it's true that the standard built-ins for javascript is poor compared to something like java.
It's not geared, imho, for a UI with lots of interactivity - e.g., imagine trying to implement blender or an audio processing app (like audacity) in html/css. You'd basically be creating new primitives on top of html, and build your UI on that (or install one of those UI libraries that _renders_ to html).
That's not a useful observation; JavaScript has that too.
> and ontop of that is built a fair number of UI frameworks like swing
Swing is what I was thinking of; I've never gotten the impression that anyone liked it.