Avoid using global variables
For a big company like facebook, I see the problems of CSS and finding another solution to them is fine but asserting like *we don't like css, we won't use it so you don't use it too * is something different. You are facebook, do it however you like but don't drive the people into different directions and ruin standards.
All of these are valid arguments. I don't see Facebook's presentation as a call not to use globals in CSS, though. It is more about being able to isolate CSS when needed, which is a shared goal with Web Components standard. React provides a nice "component" abstraction, while CSS Modules spec (https://github.com/css-modules/css-modules) solves the issue. I have written a library https://github.com/gajus/react-css-modules that brings React components very close to Web Components without any headache about legacy browser support. CSS Modules themselves allow local scoped CSS, which allows better semantic naming, composition pattern that can represent the entire element state, to name but a few benefits. Therefore, hurray for the innovation.
Really looking forward to React taking on CSS. Structure, behavior, and style all in one component file! Gonna be amazing.