Genuinely most terrorists are mentally handicapped. They groom, coerce and exploit low IQ individuals, because those are the people you can convince to blow themselves up (or whatever else).
OK, if that makes you feel better. Most of the 9/11 hijackers weren't low-IQ individuals; they included engineers, architects, schoolteachers, and pilots (for real); many were recruited out of universities; many were bi- and trilingual; &c.
It doesn’t make me feel any type of way it’s just an observation that has been made. You can find interviews with ex-terrorists where they detail how recruitment is done and how work is delegated.
Terrorists organizations are members of high control (ie. cult) groups.
High control groups succeed because they apply their tactics to people who at vulnerable. Vulnerability has no correlation with intelligence. Lots of intelligent people are exploited by high control groups because they are recruited at a time when they are vulnerable.