Why does misguidance afflict the ignorant, but not the intelligent and learned?

Ibn Hajar al-Makki al-Shafi'i stated that obsessive whispering (waswasa) is caused by ignorance, extremism, and excessive scrupulosity, and that it indicates a deficiency in intellect and knowledge. One whose knowledge and intellect are complete does not suffer from waswasa in their worship, for the religion of Allah is ease. Knowledge is one of the greatest remedies for waswasa. It was narrated that Ahmad ibn Ata's chest was constricted due to excessive use of water (in purification), then he heard a voice saying: "Forgiveness lies in knowledge," and that (affliction) then left him. Waswasa originates from ignorance and leads to blameworthy innovation and excessive scrupulosity, and knowledge is its cure.