The causality is the same, they are and were fanatics.
Anyone that has a strong enough belief in something, right or wrong, will die for those beliefs.
I am saying that if they are martyrs and killed for their beliefs, or kill others because of their beliefs, it doesn't tell you whether those beliefs are right.
Just because a person is willing to kill or die, does not necassarily make their beliefs true, in any sense of the word.
See how restating your position changes what you said dramatically. I thought for a moment there you were equating early Christian martyrs to modern Islamofascist terrorists.