@Maximilian,
Please consider Qur'an verse 5:32.
"
whoever kills a soul unless for a soul or for corruption [done] in the land - it is as if he had slain mankind entirely. And whoever saves one - it is as if he had saved mankind entirely.
"
Admittedly 5:33-38 are very harsh. But continuing to 5:39 and 5:40:
"
But whoever repents after his wrongdoing and reforms, indeed, Allah will turn to him in forgiveness. Indeed, Allah is Forgiving and Merciful.
Do you not know that to Allah belongs the dominion of the heavens and the earth? He punishes whom He wills and forgives whom He wills, and Allah is over all things competent.
"
ISIS is in violation of these verses because they are subverting Allah's dominion and they are preventing a person from repenting from their wrong doings.
You said "Islam is ISIS. ISIS is Islam. Everything they do is absolutely completely consistent with the Qur'an."
You are wrong.
This represents a factual error. ISIS is not absolutely and completely consistent with the Qur'an. ISIS is not Islam and Islam is not ISIS. Please rectify your factual error per your statement above.