First, let's be clear here: React was first open sourced in 2014, being used at Facebook extensively before that. Sure, it's no Win32 API, but it's not exactly the new kid on the block.
But the point of the web already having these standards is exactly the point - these frameworks are built on top of and contribute to the underlying universal standards, so what's the problem?
There's this cargo cult complaint where people talk about 'layers and layers of bad abstractions' while rarely offering a superior solution or describing exactly which abstractions are bad and why they are bad. Mostly just hemming and hawing about things being "bad" and "overcomplicated".
It's basically the same instinct as complaining about code written from a previous dev that you didn't write--because you didn't write it, you weren't there to think about the very real tradeoffs that always have to be made when actually implementing something, rather than just complaining about the previous person's implementation.
I never know which abstraction people are complaining about. Is it http? html? the dom? javascript? wrapping libs like jquery? view frameworks like react? routing frameworks? complete frameworks like angular? what's the solution? get rid of all of those things? use different UI abstractions? get rid of javascript ?(oh wait, you can already). The truth is, it's just easier to complain than it is to implement, so that's what people do.
But the point of the web already having these standards is exactly the point - these frameworks are built on top of and contribute to the underlying universal standards, so what's the problem?