nods Makes sense to split it up, but I would add a fourth and very important issue: many of the large Muslim immigrant communities in Europe (or at least the Moroccans and Turks in Belgium and the Netherlands and I'd guess Germany, those are the only ones I can really comment on) are not some kind of representative sample taken from their homeland. They, or their parents and grandparents, were recruited in the poorest and most conservative rural areas of these countries. In the decades since they left, their home countries have changed and modernized a lot - but they don't (fully) see that, they have the immigrant's typical outdated view of the homeland. Obviously they too changed in their host countries, but in many cases not as much as they should have - too concentrated, too much living apart in their own communities and putting up united fronts against the rest of society.

Which is how you get to the strange situation that caused the big diplomatic incident in the first place: Erdogan and the AKP get their best scores among the millions of Turks in Germany, the Netherlands, Belgium etc. Better than in all but the most rural and conservative parts of Turkey itself. It's entirely plausible that Erdogan wins his referendum narrowly thanks to the votes from abroad - people who have their democratic rights in Germany or the Netherlands or wherever, voting to restrict those of their brethren in Turkey because of their distorted view of Turkey.

When it comes to things like honour killings, those characterize almost exclusively the most conservative, left behind communities in the Muslim world - it just so happens that that description includes a number of people in Europe.

How do you test for all that stuff on refugees coming in? If you're talking about other categories of immigrants - there aren't exactly a lot of those coming in anymore, though I suppose you could further restrict family reunion policies in some countries. But the biggest problem is that many of the people you describe aren't immigrants, they're born here and sometimes even more conservative than their parents, or at least less tolerant - some teenagers rebel against their parents by acting out or boozing it up or flirting with minor crime, others do so by becoming Salafists and trying to join IS in Syria. And if you'd go so far as to consider expelling people who were actually born in your country to their ancestors' homelands: they don't really fit in there either anymore, for the reasons I mentioned above.

I don't entirely disagree with you - multiculturalism is a problem if the different communities remain too segregated, as has happened in many cases in Europe with the Muslim immigrants, much less so in the US or Canada where they were more thinly spread, inevitably less tied to their homelands, and in many cases wealthier and higher educated to begin with. But they're here now, and simplistic solutions aren't going to solve the problems we have. At best, far-right parties like Wilders' have a role to play in keeping the pressure on the mainstream to try and find solutions - and a perhaps less obvious role in promoting political consciousness among the immigrant communities through their hostility, forcing them to engage with the rest of society.