I wouldn't say that React is particularly huge compared to other frameworks. Certainly when if first came out it was actually quite small. I haven't checked lately, but I think it is still considerably smaller than things like jQuery.
But you answer your own question in the second paragraph. Why use React? Because you want to use a non-standard functional style of Javascript. For me, it's a pretty big advantage, but if you don't like functional style programming and can't deal with persistent, immutable data structures, then I think you would be wise to avoid React.
To a certain extent I can sympathise with your feeling. Almost every time there is an article linked here on HN I see people getting into trouble with React. Usually the solution they reach for first is to strap on more plugins (with Flux, etc). Often the structure imposed by those plugins help them be more disciplined, improving their code, but at the cost of added complexity.
React itself is very simple. The trick is in understanding how to use it. Things like componentDidMount are useful for very strange corner cases, but it is pretty common to see people use it in every single component they write. If you pull componentWillReceiveProps, etc out of the box, then it should be a gigantic clue that you have done something very, very wrong. Mostly there are warnings in the documentation about this. Mostly people ignore/don't read them ;-).
JSX is really a non-issue for me. Personally, I don't understand why anyone would want it. You can write exactly the same code without JSX and it looks pretty much exactly the same (except with lots of insane, silly parentheses -- but, we're here for the functional, right?). Whatever. Normally I have to browserify my code anyway. Adding another step to the build is not exactly rocket science. I'm also usually using either coffeescript or ES6 through babel, so I've got a compile step either way. The times where I insist on no JSX is when I'm doing ES5 work and want to run unit tests in Node without the compile step. But that's pretty rare.
Having said all that, I'll take the opportunity to offer you some advice. I don't know if you are in the mood to receive it, so it might be fruitless. You said:
> Whatever happened to pragmatism? Has that just lost by the wayside of the new shiny?
One of the things about smart/talented developers is that they are used to growing up thinking that they know the right answer. I was certainly of that mould. As I've gotten older, though, I've realised that this way of thinking is self-referential and ultimately limits your growth.
In this case, I think you've decided apriori that the way you are comfortable doing development is already the best -- or at least so much better than what you see elsewhere that it doesn't matter if it's the best. When you see people struggling (and failing) with something new and unfamiliar, the natural inclination is to assume that it is no good.
Did you know that back in the day, many programmers thought that MFC was an exceptionally good idea? Anybody forced to use that anachronism now would probably quit on the spot. Things do get better over time and new frameworks and techniques can improve our lives as programmers. While it is pragmatic to stick with what you know, you have to balance that with learning new ideas that make you a better programmer.
Humility has always been something I struggle with, so perhaps I am the wrong person to say anything. However, when you see someone making the same mistake that you made over and over again, it behoves one to speak out, doesn't it?