That is certainly true; compared to Angular 1's shenanigans, it was far harder to accidentally make React slow, so of course word quickly got around that it was

That is certainly true; compared to Angular 1's shenanigans, it was far harder to accidentally make React slow, so of course word quickly got around that it was faster than Angular.js (something interpreted as just "fast"). However, I'm not sure if I'd call that the motivation behind it, or even conscious marketing from React's side, rather than just an artefacts of its times.