The senior religious scholar in Egypt, the Grand Mufti Shawqi Alla, recently denounced ISIL (Islamic State in Iraq and the Levant). This was just another ISIL critic on an already long list of religious scholars risking their lives to denounce this murderous and vindictive group. ISIL regularly reminds everyone that any cleric preaching against the group is considered to be un-Islamic and subject to attack by ISIL death squads. When ISIL shows up in an area the clerics become a lot more discreet in their criticism, often to the point of silence about ISIL or a quick departure to a safer location.
Islamic terrorism has long been trapped in a self-destructive cycle of its own making. It works like this. Islamic radicals obtain their popularity and power by proclaiming that they are defending Islam from non-believers and sinners (within Islam, often local Moslem dictators). In order to maintain this moral superiority, the Islamic radicals must be better Moslems, and insist that others do as they do. Since Islam is a religion that dictates how one lives, in considerable detail, as well as how one plays, this business of being a "good Moslem" can get tricky. And it is. There's a race underway by Islamic radicals, and the clergy that provide theological support, to issue, and enforce, more and more rules on how a good Moslem should live.
For example, back in 2009 a Saudi Islamic scholar issued a fatwa (a religious ruling by a qualified religious official, although unqualified clergy can try to issue these and hope that people will obey) banning the use of alcohol as a substitute for petroleum in vehicle fuel. The reasoning was that the Koran forbids the use of alcohol for any use, not just for drinking. The fatwa applies to all Moslems, everywhere.
At the same time the Indonesian council of Islamic Clerics, the senior fatwa issuing authority in that country, issued a number of interesting fatwas. One banned smoking in public, or by children or pregnant women under any circumstances. Another allowed men to marry child brides (as young as 9). This one might be a problem, as Indonesian civil law makes it illegal to marry a woman under the age of 18. Islamic clerics justify this because the Prophet Mohammed consummated his marriage to a nine year old. The sex with minors thing has been going on in Indonesia, with the assent of the clergy, for years, and only became an issue when a clerical group sought to have the civil law changed to make such activities legal. Meanwhile, in Saudi Arabia, civil and religious officials are arguing over the same issue. The clergy are arguing among themselves over the idea of marrying young girls, and civil officials are against it. But many Saudi men are for it. This is particularly tricky for the image of Islam. Living according to the Koran, and rules drawn up in 7th century Arabia from contemporary customs ignores over a thousand years of social, medical and scholarly progress. Most of the world, including most Moslems, have embraced the modern world and have no interest in dialing back from the 21st century to the 7th.
The problem with controversial issues like this is that, once enough clergy get behind some lifestyle rules, they also grant permission for religious vigilantes to use force to enforce these rules. Saudi Arabia and Iran have lifestyle police that can arrest, and imprison you. The God Squad can also use force to restrain (arrest) offenders, and often do. In Saudi Arabia, this has gotten so bad that the king fired the head of the religious police. There were growing complaints from the public about the rough treatment they were getting from the religious cops, and the king agreed that things had gone too far.
In the late 1990s, the Taliban in Afghanistan made themselves so unpopular with the use of their lifestyle police, that they lost control of the country after the U.S. intervened in the civil war (against some northern tribes who had not yet been conquered by the Taliban) with a few hundred Special Forces troops and CIA operatives (and a few hundred smart bombs.)
The Islamic radicals have not come up with a way to avoid this trap. Every time the Islamic radicals gain power, they begin implementing stricter, and sometimes absurd (even to many of the locals) lifestyle rules. When the radicals try to enforce all these rules, the people eventually push back, and the religious dictatorship falls.