Right so even then, its a bit weird to say that 25% of sites decided to not go with React, but actually 25% of sites (unknowingly) use software that decided not to go with React.
No, he's not. He's pointing out that calling it an "exodus" implies that many individual projects have decided to abandon React. In this context WordPress is just one project, not "25% of all websites".
WordPress runs 25% of all websites. That is huge. You're trying to trivialize it as being "just one project" when it's really one of the most widely used and significant projects out there. One decision that WordPress makes is worth tens of thousands of decisions from much smaller projects that aren't used very widely. WordPress is a many billion dollar a year industry in itself, and whether it uses React or not will directly contribute to many thousands of web developers out there learning it or not.