They are deluded if so, every terrorist attack sparks a stupid knee jerk reaction from the West.
I suspect they do it because it plays into the narrative of West against Islam, doesn't help much there is also a nasty right wing element in the West which will gain power with every successful terrorist attack.
Short term there will be air strikes to be seen to be doing something or revenge, but as in Afghanistan, it is difficult to hold territory or maintain rule of law without ground troops and a political solution, and in the long-term there will be a reduction in foreign ground troops.
ISIS are probably gambling on being able to put out images of dead civilians from air strikes on the internet to play into the anti-Islam narrative and inspire and radicalise some disaffected violent young men to carry out some kind of terrorist attack. Even ISIS's claim of terrorist attacks against Russian civilians doesn't prevent Russia from attacking those who oppose Assad, even if they also oppose ISIS. So ISIS will find room to manoeuvre amongst the political in-fighting and they have some powerful allies.
I think ISIS would welcome a rise in the right-wing elements in British society - apart from enjoying the conflict in liberal societies, people being nice to Muslims would actually worry ISIS more as it disrupts their anti-Islam narrative. So even if mainstream Muslim voices condemning ISIS ideology are getting more media publicity the moderates will find it hard to counter the frustrations of disaffected young people experiencing right-wing anti-Muslim prejudice who are drawn to the ISIS call to fight back by taking part in the "glorious" battle by any means necessary .