What makes this observation particularly sharp is that King isn't warning against malice—he's identifying something far more insidious: the person who acts with genuine conviction while lacking the self-awareness to question their own understanding. A well-meaning parent who raises a child with strict certainty about the "right way" to live, never pausing to consider whether their child's different temperament might require a different approach, embodies this danger more than any openly cruel person. The conscientious fool causes harm precisely because their sincerity makes others trust them, while their ignorance goes unchecked. True safety, King implies, requires not just good intentions but the humility to wonder whether we might be wrong.