Firstly, what interpretation of Multiculturalism are you using?
There is only one interpretation of Multiculturalism and that is people of another culture live and work among us and dont cause problems... preferably also integrated.
A bunch of morons who pander to the far right.. sorry but you can not do policy to
force multi-culturalism or in fact integration. It has failed at every attempt even in the US which is the birth place of modern so called multiculturalism. Integration of minorities takes decades if not centuries. The Asian population of the UK only came to the UK after the fall of the British Empire (for the most part). That is only 60 or so years ago. The first generation migrants are in many cases still alive! This does not happen over night.
Like it or not when you move to another country (I have moved to several) you tend to try to find like minded groups, usually from your own country. If you go to any country with a large expat community, then a huge portion of those people only interact with their own countrymen or other foreigners. Even here in Spain that is quite evident for most people..We have large areas of British only here.. hell the regional government had to step in a few years ago to force store owners in a small town near here to have signs and menus in Spanish, because everything was in English! Over time of course you get more and more comfortable with the locals and get local friends. But it takes time, and requires a willingness from you to do so.
So why on earth would Muslims or whatever be any different than your own country men when moving to another country?
What traction it's getting is hard to discern. Keep in-mind, Cantle has worked vigorously on this since the riots of 2001. In that report, the lack of community cohesion was seen as the tinder for mistrust etc. Fast forward to 2016, it's not some gigantic leap of faith if we suggest this is in some way contributory to those that flock to the banner of Daesh.
Mistrust comes from ignorance and stupidity. Why? Because a few rotten eggs taint a whole community and that is what happens with minority groups. It is a sad fact but true. Look at the white Christian community. Does crime by a white Christian taint all white Christians and their attitudes to said community? Of course not.
But take a black Muslim or Asian Muslim doing something wrong and bang it is the fault of the community in not only stopping him but not helping the police to stop him/them.
So of course these minorities see it as an attack on them and they band together to defend themselves against what they see as an attack from the outside. The more they band together, the easier it is to "brainwash" them out of fear. Look at any right wing racist organisation. Why do people think like BNP or UKIP? Because the band together and re-enforce a common belief of us against them and what to do about it. This in turn fortifies both sides and so on and so on.
You want to reach into Muslim communities to stop DAESH? What you have to do is easy, but hard to actually carry out.
1) The Imans in Mosques need vetting without it looking like it is the state appointing them. This is tricky as hell. The Iman is the key to the community, just as the Rabi is in the Jewish community. Have westernized open Imans and the problem dies down considerably. But if you dont allow the community to appoint their own then that will cause problems as well. One way would be to create with the community organisations a vetting process and education system for religious leaders. However you have to do this for all religions..... it could help with the child abuse in the Christian churches..
2) Stop blaming all Muslims for the acts of a few. This is critical and hard as hell to do with UKIP/BNP type people out there.... let alone the right wing who use it as a political weapon of fear to gain support.
3) Stop calling Islam an evil religion.. this alone has rallied many people around the extremists who use it as a rallying cry... Islam is under attack!
4) Reach out women and girls.. the laws are already in place.. Girls HAVE to have an education and freedom. This alone would do wonders.
5) Ban religious based schools. If they want to learn religion.. go to the Mosque/Church school on their own time which has to be controlled by the state to make sure no extremist ideas are being taut. Schools should be for learning facts.. not facts tainted by religious dogma. Any underground schools or teachings should be hit down hard on.. prison and deportation of the teachers.. I have zero respect for these terrorists regardless of the religion.