That is a very good point here. A stupid intelligence system (the one that explores too little of the solution space) can do things that are grossly suboptimal, but are nonetheless rational in the narrow sense that the system did take the effort to try to explore solution space and to pick best solution. Humans though tend to choose what parts of solution space to explore based on all sorts of biases, many of which are outright irrational, in the sense of not being backed with correct reasoning, or being backed with deliberately faulty reasoning as a cover story.