I think what he meant was that he was probably a brainwashed kid from a terribly backward / underdeveloped area with hardly any meaningful economic opportunities and low levels of access to justice and protection. The state neglected FATA for decades. He was probably educated in a madrassa, if at all.
Then these people with guns and tech and cash come around saying you can have an AK in this life and heaven in the next. Suddenly, you are empowered. You have a sense of purpose and divine justice. And you are drugged/brainwashed further to believe that the Pakistan Army is upholding an illegal secular state and therefore is a legitimate target. They are also responsible for XYZ (made up / exaggerated crimes with doctored photos/videos, etc.). Finally, you are given the best possible description/fantasy of all the wild sex you'll have with beautiful maidens in Heaven.
99% of us in that situation would probably be willing to do whatever it takes as well.
The deeper blame goes to the backers of these movements and the government's lack of development/madrassa reform/"correct" Islamic narratives to battle intolerance.
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