React is definitely a library, trust me - I've been working with Angular since version 1.2 too =) and the difference between a framework and a library is pretty obvious: A framework does everything out of the box, while a library does only one basic thing and has to be coupled with other libraries, third-party or not, to cover app life cycle.

With frameworks you are more or less consistent and follow more or less best practices (as they interpret them), but you are tied to the vendor (hello Google and its graveyard of projects). With libraries you're more flexible, but you have to worry about consistency, architecture, cross-compatibility and updates, and that's a hassle.