Doesn't this lead you to, perhaps, question the category and measure of "intelligence" in general, especially how it is mobilized in this kind of context? Like this very angle does a lot to point out the contradictions in some speculative metaphysical category of "intelligence" or "being smart," but then you just seem to accept it in this particular kind of fatalism.
Why not take away from this that "intelligence" is a word that obtains something relative to a particular society, namely, one which values some kind of behavior and speech over others. "Intelligence" is something important to society, its the individual who negotiates (or not) the way they think and learn with what this particular signifier connects with at a given place and time.
Like I assume you don't agree, but just perhaps if we use our "intelligence" here we could maybe come to some different conclusions here! Everyone is just dying to be like mid-20th century behaviorist now, I just don't understand!