Even more than most other first-world nations modern Europe suffers from a potentially fatal cognitive dissonance. All the time we hold two wholly contradictory ideas in our heads.
The first idea is that our countries are multicultural paradises where anyone from anywhere in the world can come and deserves to settle if they so wish. We believe that those who come here will assimilate, but at the same time we do not especially mind if they do not, and offer no incentives for them to do so. Indeed if they do not wish to assimilate we respect them for holding on to their own culture. At the same time it is natural that we should decry as “racist” anyone who wants to hold on to what is left of our own culture. This part of our brain talks about “integration” and “radicalisation” and “violent extremism” and all the other weakly euphemisms of our time.
Yet all the time our brains hold another idea—ordinarily pushed to the very recess of our minds but always capable of breaking out. This holds the possibility that this is all nonsense. That integration if it does ever happen takes centuries to occur and has certainly not happened in present-day Europe. This part of the brain knows from observation and from an awareness of history that a strong religious culture when placed into a weak and relativistic culture will make itself felt long before it will significantly adapt. If there is a reason why we repress this instinct and favour the wilfully optimistic version of events it is because the consequences of accepting this truth are so utterly calamitous and damn the majority beliefs of a whole generation.