Heavy JS is a bit like junk food. It's fine to have a bit at the county fair and the fact that you can build a successful commercial business selling it isn't terribly surprising, but there are pretty obvious social reasons we shouldn't load it up in every meal consumers eat.
That's what articles like this are pointing out: this well-intentioned thing we're doing has negative consequences. Let's do it more moderately and deliberately to mitigate the side effects.
You see - applications. I am also developing heavy JavaScript applications where people manipulate or edit / collaborate on the content in many ways.
For me problem is with pages/documents where I simply want to read stuff, maybe have some basic filtering options and that does not require loads of JS.
Like webshops where I am customer probably don't need 80% of JS that they drop in there for browsing just products.
I understand they need JS heavy content editor side where people add/remove/modify products.
Is it you that built Epic Games store homepage, that has appealing performances on mobile because it can't be bothered to display a list of games without heavy use of Javascript? That's what "successful JavaScript heavy applications" also leads to, developers never testing these on $50 android handsets and not caring about performance the slightest.
That's what articles like this are pointing out: this well-intentioned thing we're doing has negative consequences. Let's do it more moderately and deliberately to mitigate the side effects.