Earlier quoted context omitted.
Human brains were shaped over thousands of years of adaptation for warfare. Just look at how creative and advanced the tactics of other guerrilla forces (like the Taliban and Viet Cong) got, despite their very limited resources. None of that needs a high school education.
It's not about education itself necessarily, but I'd bet any amount of money that most terrorists' IQ is below the overall human average. The average terrorist is not that innovative or creative so the most mundane GPT "insight" will likely be a smarter course of action than whatever their first idea would have been.
Fighting a much more numerous enemy may seem stupid, but if you really believe your ideology, any odds of success are better than none. Think open-source developers competing with commercial offerings maintained by huge teams. Terrorists building IEDs when their enemy has a full military-industrial complex are much the same. They just really believe their ideology. On this, https://www.astralcodexten.com/p/your-book-review-nine-lives is a good read.