Why does React require Babel and Webpack to work?

Question

I was looking at the wiki page of vue.js and saw this:

When compared to React development, Vue can be integrated to an existing web application much mor

Answer 1

Can someone explain why React needs webpack and babel? I thought you can just drop in the link to the CDN of React and it will work?

React doesn't "need" babel or webpack but the library is built on the concept of using ES6 javascript syntax and JSX (essentially HTML in JS).

React however can be used without ES6 and JSX which would remove the initial need for Babel but you would lose the potential benefits of ES6 and JSX.

Webpack is separate from React but commonly used in React projects for reasons MattYao mentioned.

In comparison to Vue, JSX to me brings the benefits of containing html, css and JS in one file/component which is what Single File Components in Vue also try to achieve. These would also require a build step using something like webpack as well.