I dislike articles like this. The vast majority of people would consider React a framework, and if you need to redefine such a basic word in order to make your point valid, there's probably an issue with your argument, not the definition.
Having worked with both, React isn't just an "opinionated way of writing JS", it uses Javascript under the hood but there's a ton it does uniquely, that is there is no JS equivalent, this is a thing that only React has (hooks, context, etc).
I agree with you that there's something slightly wrong about that framing on the part of the devs.
But this is just the old descriptivism/prescriptivism divide again.