In my opinion, this is the most dangerous statement in this thread. Saying the actions of these people is irrational loses any ability to understand why they're doing what they're doing and how we can stop them. It turns them into a faceless enemy who are doing things because of hate, which is easy and makes my ego feel better, but doesn't really explain their actions or the actions of anyone. Nobody thinks they're the bad guy of their own story.
There is nothing more rational than terrorizing civilians to achieve a goal. It is the logical conclusion of rationality.
I don't see the distinction either. If you drop a bomb and kill some people that you didn't intend to kill, you're still 100% responsible for those kills.
It is the saddest thing that we have found no better response to terrorism than limiting civil liberties and sending 18 year old boys with guns to foreign countries.