React is a rendering engine, it's covers the final piece of your web app (rendering a data structure into DOM). But whatever you do to create the data structure that gets passed to React is up to you. This keeps most of your domain logic outside the context of React, you just use React to render data->DOM. So basically the API you have to learn is just Javascript, which most people know already and is easy to lookup answers to your questions.
With Angular your domain logic exists in the context of the framework. i.e. if you ng-repeat something you can't just filter that collection with Javascript you have to use an ng-filter to do it which is a special Angular construct. So the API you have to learn to manipulate data isn't just Javascript it's Angular. And how does ng-filter work? Well, you're tied to the Angular docs to figure it out. The Angular docs are of particualary poor quality so this coupling turns into a really serious problem if you're trying to be productive.
To me React vs. Angular isn't a matter of preference like Ruby vs. Python -- it's more like git vs. FTP where there is a clear right answer if you're trying to be productive in a team envrionment.
Sigh... this is such an annoying comparison. If you want to compare, compare React to Angular Directives since that's a valid argument.
Your entire complaint is that full-stack front-end frameworks are bad and modular systems are good. It's great that you prefer modularity and the ability to mix and match tools.
But stop pretending React vs Angular is a thing. It isn't. git vs FTP... just stop.
React is a rendering engine, it's covers the final piece of your web app (rendering a data structure into DOM). But whatever you do to create the data structure that gets passed to React is up to you. This keeps most of your domain logic outside the context of React, you just use React to render data->DOM. So basically the API you have to learn is just Javascript, which most people know already and is easy to lookup answers to your questions.
With Angular your domain logic exists in the context of the framework. i.e. if you ng-repeat something you can't just filter that collection with Javascript you have to use an ng-filter to do it which is a special Angular construct. So the API you have to learn to manipulate data isn't just Javascript it's Angular. And how does ng-filter work? Well, you're tied to the Angular docs to figure it out. The Angular docs are of particualary poor quality so this coupling turns into a really serious problem if you're trying to be productive.
To me React vs. Angular isn't a matter of preference like Ruby vs. Python -- it's more like git vs. FTP where there is a clear right answer if you're trying to be productive in a team envrionment.