Hm, I don't share your opinion on this matter, to be honest. You can easily avoid this in both Angular (which does it out of the box) and React by including CSS Modules (https://github.com/css-modules/css-modules) which, if you use create-react-app to build your projects, is a 5 minute change to your architecture. So there really is no reason to write that down as a con for React.