but to say that this entire trend is invalidated by two examples
Where did I say that? I merely posted facts, which often seem to cause people who interpret things in black or white to imagine words that weren't there.
The Lord's Resistance Army is also not "Christian", it's a hybrid of Christian and Mysticism based more heavily on the 10 Commandments:
The person I responded to was using a loose definition of "Christian", indicated by them labeling Hitler as a Christian. There is a wide variety even among Christian groups in the USA. There is no standard definition accepted by all.
"Muslim" terrorists have repeatedly been denounced by Muslims who do not consider the terrorists to be true Muslims.
Is suicide bombing justifiable? Survey | Pew Global Attitudes Project
Al Qaeda Favorability Survey | Pew Global Attitudes Project
If you are going to consider Muslim extremists to be Muslim, then you have to do the same for Christian ones. You can't have it both ways.