You want to say that ISIS and other Islamic Terrorist Organizations are not Muslims, and do not practice Islam.
Saying that ISIS is not based on Islam is like saying the Black Panthers are not based on Black Power, the KKK is not based on White power, or the Catholic Church is not based on Christian power.
If a man prays to Allah, follows the teachings of Allah, and performs his actions int he name of Allah, then he is a Muslim. It does not matter if he sells sea shells by the sea shore, or if he kills and enslaves, if he says he is a Muslim, and he does it in the name of Allah, then it is Islamic. You do not have the right, nor power, to take away a person’s faith or identity based on that faith, simply because you find the idea uncomfortable, or you are too afraid of Muslims for calling out their violent elements.
That is all…for now.