Whenever there is an attack, both the snark about the "religion of peace" as well as the claim that Muslims don't condemn these acts both resurface. The fact is that both terrorism and ISIS have been roundly condemned by large panels of Islamic scholars.
It would not surprise me that, once the religious background of these terrorists is examined, that it is proves to be very flimsy.
The challenge, in my mind, and as a Muslim is that Muslims need to figure out how to prevent the brainwashing of impressionable young people in an era of instant communication.