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.
There are lots of e.g. Indian, Chinese, South-East Asian, immigrants in Europe. And all over the world. If anything, they look less caucasian than people from Middle East / North Africa, so one would assume them to face even more racism. But they have not produced terrorists.