The term is already in use. Didn't the left try mightily to make McVeigh a Christian terrorist? Even though his religious views were questionable, at best.
Al-Baghdadi, the founder of ISIS, on the other hand, was 100% Muslim. In addition, he was an Islamic scholar. Yet you imply that you know Islam better than him.
See, the difference between people like myself and people on the left is I allow the facts to speak for themselves: the facts in this instance strongly suggest that al-Baghdadi knows Islam. Actually, it would be intellectually arrogant on my part to say something like 'al-Baghdadi doesn't know Islam---his claims notwithstanding'.
The left allows their ideological commitments [to multiculturalism and PC] to trump the facts when it comes to Islam and Islamic terrorism. Filtered through their ideological prism, Islam is no different than any other world religion, 99% of its practitioners are peaceful---facts to the contrary, be damned.