The Muslim clerics of Iran and their Supreme leader are the leading arbiters of Shia Muslim "interpretation" of Islam. Their version of "peace" differs from the Saudi belief (the epicenter of Sunni "interpretation) only insofar as one is Shia and the other is Sunni. And either depiction of peace differs from ISIS (which claims to be Sunni) mostly in degree, and in the desire of any of them to maintain their own power.
The Saudi Shia leaders behead scores of people every year. ISIS (the so-called "extremists" who we want to believe are not truly Muslim) will have to go a long way to equal the number of beheadings executed by Saudi Arabia which we are to believe is the head of a supposedly true and "moderate" form of Islam.
Iran, representing the true and "moderate" Shia version of Islam, has its own hundreds of executions every year. But it also, as a matter of Koranic decree, executes and supports terrorism outside of its borders. In case we have forgotten about the fatwa against Salman Rushdie, it has been reinvigorated and the bounty has immensely grown:
http://www.huffingtonpost.com/entry/...b0928f5a6d2287
Of course, we're not supposed to be "biased" against this religion which is the most biased and terroristic one than any other major faith. It is, as we are supposed to believe, the religion of peace.