Is this same react where your components keep internal state (called state) and every component must be created by extending a base class?
> every component must be created by extending a base class
This is an implementation detail, instead of ES6 classes you can also use React.createClass(), which might as well be named React.createComponent(). These "classes" can't be inherited from.
<test_component/>
Buy even if you could write every component with the stateless style it doesn't change the fact that your framework/GUI-library is using OO extensively and in it's fundamental concepts, I think that makes it OO, you seem to disagree.
From the React docs:
> In an ideal world, most of your components would be stateless functions... This is the recommended pattern, when possible.