The number one thing that you (and Facebook) could do to help people learn React, and combat the perception that it requires overly complex tooling, is write a tutorial that shows how to use React entirely in-browser without any build toolchain. A static HTML file, some <script> tags pointing at a CDN — done. No distractions, nothing to download, nothing to install, nothing to run, just a JavaScript library that makes it easier to write view templates.
It would make it even easier to get into if that tutorial were written entirely in ES5, but you could use babel-standalone if you felt that JSX and ES6 were important enough.