The idea that intelligence is not rational may seem absurd. And perhaps it is. But that might only mean that there is a serious problem with our theories of rationality. I shall assume only traditional ideas as to what constitutes rationality. As usually understood, a theory of rationality is a philosophical theory and is usually considered to be part of epistemology.
Most philosophers consider epistemology to be a normative discipline.
As such, they likewise treat their theories of rationality as normative. That is, a theory of rationality is a theory of how people ought to behave, rather than a theory of how they actually do behave. To say that a discipline is normative, is to say that it has a system of rules or norms by which to judge. A normative theory of behavior is a set of rules for judging behavior. If you did not have rules or specifications, you would not have norms, and the theory could not be normative.