Earlier quoted context omitted.
React is a paradigm shift in UI development. If you've never tried it or a library inspired by it, that's why you're questioning the proponents. We're trying to spread the gospel that some folks found a better way to do things. Yes, I believe it is a mistake for any UI developer to delay learning React. It's fine to choose other tools later.
I come to HN regularly for advise. Should I be taking yours? I'm a web dev by proffession. React is a paradigm shift? Kind of like the paradigm shift 20 years ago where we said "separate your markup from your style, you'll be better off, promise"? Using css felt right, right from the start. I should really learn React? Mixing js and html in a react flavor does not give the the same sense of being on the right track.
In the past I tried many times to use some spare time to learn Angular, but it always felt too overengineered to me (also because it does much more than React) and I always stopped at the beginning. With React, just a few hours were enough to appreciate the concepts and get started.
Then of course you can add Redux and that will take more time, but you can almost just as well use React components with any state manager you like.