While I would agree, that Muslim Terrorism is far worse than militant Christians sects ever thought about being, I would also agree that there are many militant Christian groups that are terroristic.
Aryan Nations
Charles Martel Group
The Covenant, The Sword, and the Arm of the Lord (CSA)
Ku Klux Klan
Masada Action and Defense Movement
The Order
Army of God
The Lambs of Christ
Most of these are from the U.S., some are from France. There are far more terrorist groups of Islam origin, but Christian radicalism can be just as dangerous.
I guess if you weighed the shear numbers of militant Islamic Groups to Christian terroristic groups, one could say that (based on numbers) Islam would be more of a religion of war than Christianity, however, history shows that Christians are the only religion that believed in forced conversions and were far more militaristic and did not tolerate the muslims while the muslims tolerated christian existance--until the Crusades anyway. And the Bible is filled with stories of war.