"This" means that if Islam is so obviously blood-thirsty, and this is the only possible mainstream interpretation of this religion, then how come the vast majority of Muslims are NOT killing the infidel?

Yes, many Wahhabis in Saudi Arabia support ISIS; it's well-known this is a major source of funding. But how is this a counter to the fact the vast majority of Muslims -- are you aware that not all Muslims are Wahhabis, live in Saudi Arabia or, for that matter, are Arabs? -- are NOT trying to murder nonbelievers?

"Balderdash", you say about the article "The Phony Islam of ISIS". But what you say flies in the face of everything we know about religious texts; that they are anachronistic and self-contradictory in multiple places, and there is NO single interpretation of them. Evidently most Muslims choose not to acknowledge the part about spreading the word of Mohammed by the sword, or maybe you secretly believe they do -- all of them! -- and that they are biding their time?

The author argues that some parts of the Quran contradict other parts; that there are treatises and purported quotations of Mohammed that are meant to explain the Quran, but themselves are subject to interpretation and to varying degrees of reliability. I don't know about you, but I tend to trust the word of someone who studies religion for a living and specifically Islam to have read the Quran. Are you sure it's all "balderdash" and that this professor who teaches religious studies at college "has never read [the Quran] himself"?

But mostly I trust the reality of a world in which most Muslims are not trying to murder non-Muslims. I don't even need to appeal to authority here, just to reality.