In my opinion, ISIS is pushing and pushing, hoping for a response from the West and, ultimatley when the West retaliates, Muslims the world over uniting as one. That, I believe is their ultimate game...a united Muslim front. Oh, and I know that most people believe that there are "two" Islams..."fundamental" and "moderate", but there isn't. Mohammad only invented one Islam and there are those who follow it and those who don't.
Why do real Muslims behead captives/enemies? Why do real Muslims have sex-slaves? Why do real Muslims have child brides? Why do real Muslims kill apostates? Why do real Muslims stone women to death? etc. etc. Because that is exactly what Mohammad did. So called "moderate" Muslims cannot speak out about what ISIS is doing because to do so would be to condemn Mohammad and everything he said and did. Muslims believe that Mohammad was the perfect man and all Muslims should seek to emmulate him and his life. Well, ISIS is doing just that. People have to realise, that Islam is more than just the Qu'ran....Islam is the Qu'ran and the hadith and the sura...Everything Mohammad said and everything Mohammad did is equally as important. Mohammad was a psychopath, a liar, a thief, a mass murderer, a rapist and a pedophile...that is historical fact from Islamic writings, but he is still considered that most perfect man who ever lived and all of his words and actions were sanctioned by God himself. Anyone who knows anything about Mohammad and his life and still chooses to follow him, tells me everything I need to know about that person and that is a person I want nothing to do with and a God I want nothing to do with. I don't believe in the myth of the "moderate" Muslim...I believe that anyone who sanctions and believes in a man like Mohammad is NOT a harmless, moderate person. If Mohammad came back today he would look at ISIS and say "That is Islam, that is what I wanted" and he would condemn "moderate" Muslims as weak and probably apostates.
ISIS is Islam, full stop. Unfortunately, people in Western nations refuse to accept that..why? Because if one recognises that there is a problem then one has to do something about it and it's all too hard and dangerous to do so.