The reasoning goes roughly like this:
* Highly intelligent people are not in a "protected class" under federal constitutional law
* Because of that, discrimination can occur on the basis of high intelligence as long as the government or other covered entity can articulate a "rational basis" for their decision to do so
* There is no other source of federal law that forbids discrimination against highly intelligent people in hiring
The standard is higher (and called intermediate scrutiny) for gender-based discrimination.
