I find it very weird that people still blame western politics for this kind of attacks.
The terrorists themselves are telling you they kill in the name of god. They are telling you the whole world is supposed to be an Islamic state and you keep blaming 19th century colonialism?
Stop looking down on them and realize that just like you they say what they mean. You do not need to analize them and find an alterier motive.
This war is between the liberal secular world and the closed riligious world. Stop looking for justifications for their acts of horrific terror!