> The diagnosis criteria for most mental illnesses include that the patient is negatively affected by their specific symptoms.
This is a false claim. The only requirement is that a psychologist deem you mentally ill. For example, in the eyes of psychology, Bill Gates, Albert Einstein, Isaac Newton, and Thomas Jefferson all are/were mentally ill -- that is, until the imagined malady they were supposed to be suffering from was abandoned because of public outrage.
In the same way and with the same effects, homosexuality was a lucrative mental illness until the public forced psychology to accept that it is not an illness and abandon it.
These are two among dozens of examples in which psychology invents illnesses, then offers bogus cures, all for a fee.
> Or regarding the specific quote, in the context of going to a normal school, "severely gifted" might be the right word for describing these children.
That's absurd. It stigmatizes a gift, an example of nature's occasional generosity. To an adult, the absurdity of this kind of writing and thinking is obvious. But to gifted children, most too inexperienced to understand psychology's real role in society, it constitutes yet another burden in their formative years -- years spent in therapy listening to an intellectually handicapped person exhorting them to try to be more "normal."
> If these children are given something meaningful to do in school instead, then the moniker would not be apt.
I agree with your point, but it's never apt -- it stigmatizes the gifted without recompense. You seem to be missing the point that (a) public schools are notorious for failing the gifted, and (b) this kind of talk only shifts the burden onto the children and away from where it belongs -- on our broken educational system, and on psychology.