Terrorism evolves from continuous brutal state aggression(killing of innocent)
Afghanistan & Pakistan tribal areas are facing the same situation but the opinion is polarized due to a very long stretch of WAR in these areas starting from 1979.
Lets take an example from recent history, when Iraq was invaded to take control of WMDs. And on its way they killed millions of innocent Iraqis, disabled millions of other innocents & snatched the earning hand from millions of innocent families. And today the invaders justifying their stay to get rid of terrors from Iraq. So it would make easy to understand the root cause of terrorism.
I will appreciate any arguments the other way around.