Isn't part of the problem that extremists WANT there to be more division, so the more that all Muslims are shunned and feared in Western societies (as well as pretty much everywhere else I guess?) as well bombed in the Middle East by various forces from across the world, the more hate is bred and the more of them side with ISIS/other extremists? I don't know who said it first, it may even have been in this topic or another here, but I also see it brought up sometimes when stuff like this happens...
I also think the IRA were easier to hit back at, since they seemed to be an extremely organised lot with mostly known players and pawns. Islamic extremists seem to be a whole other level of crazy, if religion is the ideology that makes them brave enough to kill themselves, then at that level of brainwashing nothing can really win, and with the large numbers of Muslims across the UK there's no way we can win unless we actually do become a police state, which is a pretty scary thought. It will make everyone else, as well as Islamic religious extremists hate them even more than they do now, so wouldn't really "win" much either. I think the way forward is like how it used to be in the IRA's peak activities, or like Syria is just now, or how Israel or Lebanon used to be. That these things start to happen but we become hardened to it and just shrug and get on with it...
Also saw this interesting chart on a forum or comment thread somewhere...