That said, there's a reasonable case to be made that this is ISIS "branding". What their leaders truly believe is unknowable, but we can see their masterful use of propaganda, with smiling jihadis next to happy-looking children, and of course also the brutal beheadings shot in high-definition using modern techniques. I doubt the Prophet approved of HD cams.
There's also a good case to be made, as in this article from The Atlantic, "The Phony Islam of ISIS" ( http://www.theatlantic.com/international/archive/2015/02/wha... ) that "literal" intepretations of the Quran and other Holy Texts are a red herring. You cannot claim there is a literal interpretation; just an interpretation that claims to be literal. But holy texts are rife with ambiguous and contradictory paragraphs, as explained in the article -- you can find an equivalent of "You Shall Not Kill" and in a different verse "Kill The Infidel", and you need some Wise Man to explain to you "ok, you shall not kill believers, but you can kill the unbeliever, unless there is a full moon (as mentioned in verse XYZ), in which case you can only kill goats". But this is the Wise Man's interpretation; by definition there is no single valid "literal" interpretation. And once you accept there is some degree of interpretation at play, you can no longer claim ISIS is evidence that Islam is fundamentally more blood-thirsty and terrorism-prone than other religions; just that some of the current high profile terrorist organizations are using their reading of the Quoran to justify their actions, and that they claim their interpretation is the "purest".
Even within ISIS and Al-Qaeda there is doctrinal dispute, as evidenced in this other article from The Atlantic, "What ISIS really wants" ( http://www.theatlantic.com/magazine/archive/2015/03/what-isi... ), which shows fundamentalist clerics disagree, and this creates splits. How can this be, if all of them believe they are following "pure, unadulterated Islam"?
