Members of ISIS are willing to die for their cause, does it mean it is true?
Yes, because they're Christians, Floo!
Oh no, wait a minute ....... No, it's because Islam's beliefs are obviously illogical and silly, not like Christianity's beliefs!
I mean who ever heard of someone being crucified and finally killed by being stabbed with a spear and then coming back to life. Silly Muslims! Oh no, wait a minute ... you're getting me all confused, Floo