Just because a web application uses React and is slow, it does not follow that it is slow because of React.

It's perfectly possible to write fast or slow web applications in React, same as any other framework.

Linear is one of the snappiest web applications I've ever used, and it is written in React.

Does not, in the seeming absence of other snappy examples and the overwhelming evidence of many, many slow React apps, the exception prove the rule?