On the contrary, they are the most exact practioners of Islam. They exemplify Islam.
If they torture, murder and rape - that is ok. As long as they help the cause of Islam.
Islam at its heart is a very simple "faith". Do whatever you want - anything at all - including any devilry - including any lie - including (suprisingly to Western ears) denying Allah - just as long as whatever you do furthers the cause of Islam. It is that simple. It is that demented.
“I have been made victorious with terror” -— Muhammed