I think the point is that many people in the wild conflate the term “REST API” with “arbitrary interaction over HTTP”. We’ve all seen examples, the one-off endpoint to fetch that little tertiary bit of data, that one-off POST to invalidate a cache. None of that is REST
To REST purists, APIs must use HATEOAS to be considered REST.
"HATEOAS" is pretty much the only thing REST contains. "REST API" without HATEOAS has no meaning, it's just a stand-in for "good HTTP citizen" (if even that).