He's definitely not stupid, we have seen that many times. More importantly, though, his ways of thinking, living, and interacting with others aren't similar to average book lovers or other heavily culture-minded people seeking jobs in libraries and similar institutions. So, he'd think outside the box compared to most of them. I reckon he's also held back less by the customary Japanese hierarchy and seniority-oriented social order than most. He's a punk, after all, with the rebellious spirit in his blood.