When most people talk about React, they aren't talking the single library, but rather, the ecosystem of libraries that enable you to build applications. Most "frameworks" are just a collection of libraries too - the difference is in branding, and most frameworks are really just a pre-built package.json/Gemfile/etc.

I'd venture to say that very few if any of the sites Facebook lists at https://github.com/facebook/react/wiki/sites-using-react are using "React the view library" by itself.