It's interesting that you find it difficult to admit that people who claim to be Christian in their heritage and belief can be terrorists. Maybe there were Christians among your own ancestry and you feel an obligation to shield them, or yourself, from guilt by association.
I don't believe that any true Christian would become a terrorist, neither would a true follower of Islam.
Terrorists will hang their hat on any religious peg to justify their actions.
Pure and simply terrorists are Bombers,Murderers,Rapists and thieves, and should be purged out of existence.