Attacking the Root Cause

In reference to the USA attacking countries like Iraq and Afghanistan in order to destroy their terror support infrastructure, a friend made the following remark. He said that if one's house was infested with bugs, one has to fumigate it rather than going to neighbors house and start exterminating those bugs there. But I had a different view on this: 

Acharya Chanakya showed how to deal with an enemy as little in appearance as a thorn. When a thorn hit his leg, he did not just pull out his leg out from thorn (or the other way around) and moved on, but he pour sugared milk over the place so that ants could eat up and destroy the root of the thorn inside the ground. That was his way to deal with a problem - always solve the root cause. Therefore, if fumigation of our own house is the way, perhaps we would need daily fumigation till eternity. On the other hand it might be better to get the root cause exterminated even if it lies in neighbour's house! In any civilized country law allows that - you can't play music too loud or you can't be a threat to the neighborhood and law would deal with us if we pose threat to others. So I think there is nothing wrong in curing the root cause. 

So we can't blame USA entirely in what it is doing.