Sorry if I wasn't clear. What I meant by "Defeat the IS "ideology" on an moral, intellectual and religious basis making it unattractive for new recruits" was purely aimed at stopping the flow of new recruits. Yes, the others will have to be defeated some other way. Militarily more than likely.
Yes, the IS are fundamentalists who perhaps want to live like the prophet (I'm not totally convinced), but that in itself is an interpretation of how the prophet lived. (There is no 100% accurate 'Diary of the Prophet" to follow, and there's no Kalashnikov, rocket launcher, oil refinery or SUV in the Quran or Hadith, and they can't turn the clock back). It's their interpretation of the Quran, Hadiths, Sira and Sunna versus other interpretations. The folks of the IS are justifying their actions by words, by quotes from the Quran and from various Hadith. They are recruiting using words, producing "glossy magazine" style PDF files (available to download on the internet if you search for them), using Facebook, Youtube and Twitter, all with their own take on religious justifications for their 'cause'. It's a battle of minds as much as anything. An intellectual battle. Propaganda, if you will. But it appears to me that IS is winning the propaganda war. Propaganda. Words.
And when I wrote "senior religious thinkers, scholars and academics", I thought it would be clear that I didn't mean just "some Imam".