Islamic terrorism. Why does it exist? Is there something inherent within the religion itself, or a reaction to Western activity?

I think you can have terrorism with any extreme viewpoints. When your viewpoints become more important than people, and you are willing to kill, then you are a terrorist.

This happens with hard right groups, happens with hard left groups, happens with labor groups, happens with business groups, etc.

Currently, we just have an area of the world where these type of groups are thriving for a huge number of reasons. In that kind of environment, they are able to export their brand of hatred across the world.