The puppeteers are the ones that matter, the 'terrorists' are for the most part tools in the hands of masters at playing them believing they are making the world a better place (and how wrong they are).
I make no distinction between idiots of any plumage, be they muslim, Christians, atheists or something else, organized or acting alone. They're a plague on society and should be dealt with, preferably long before they can become a problem in such a way that becoming a problem never even enters their minds because they're too busy living and appreciating life.
I don't doubt it but those don't typically go around committing mass murder.
As far as the 'people are willing to kill and die for them' bit goes, that's a pretty good definition of insanity to me. After all if an idea was placed in your head and you then go out and use that idea as justification for murdering innocents that you have no personal grievance against (the one universal that most people seem to agree on is a bad thing) then there is something not entirely right in your head.