The term neurotypical doesn't have to be scientific to have meaning. The term is very strongly associated with autism and ASD, and that's the context in which the term was used here. Using an existing, loaded term in reference to a person's behavior, prefixed with a "I'm not diagnosing any conditions," fig leaf is disingenuous.
Personally I am inclined to avoid the term "neurotypical". Although the term is popular, it is unclear what exactly it means, and the scientific basis behind the term is questionable.
That said, RMS clearly displays traits consistent with the broad autism phenotype (BAP). That's not a diagnosis because BAP is by definition not a diagnosis – it is defined as a subclinical condition, and by definition you don't diagnose subclinical conditions.
