I have no problem with jQuery (I still use it on animation heavy websites), but Backbone wasn't a good framework IMHO. it was not very useful and it lacked the component model that is well understood by web frameworks today (backbone didn't support composite views).There is no reason to use Backbone nowadays.
I think Vue.js is a good replacement for the people who seek simplicity and a clear data model. And it doesn't require any asset pipeline or whatever, it's just a little JS file.
Angular 2,4,whatever and Embers are frameworks that oozes with complexity, for very little benefits in my opinion.
Nested views were problematic, undeniably, and did lead in the real world to a big old mess that wasn't much better than the jQuery spaghetti it was intended to replace, with events bubbling all over the place and unnecessary re-rendering and so on. I led a team that built a big Backbone app, back when it was very much in vogue, and it was certainly hard to get this stuff right in practice - perhaps not impossible, but harder than one would have preferred.
Shaming shouldn't be a thing, but It's fair to say no one should start a backbone project in 2017, unless it was dead simple, in which case you can use pretty much any tech anyway.
However, that doesn't mean the new libraries/tools/technologies are just created because "oh it's been a year and we're still using knockoutjs/react/angular/webpack/yarn!", but because a slight paradigm shift happened - at least for some people - and they feel that backbone is not the ideal tool for their job. (Maybe they felt backbone is too barebones, and went for angular, then felt that too heavy, and tried React and settled for Inferno.js.)
> "Oh, why are you using Backbone? That's an old and obsolete technology. You should learn React/Vue/Elm."
(Vue is easy to learn for new devs, though)
The dev is not familiar with functional programming or other paradigms that React suggests or requires you to know. He may be in a early learning process where Backbone/jQuery makes it easier for him to start on building webapps.