I don’t want to get in the middle of a flame war, but as someone who’s seen the culture of his small town shift over the last couple decades, I can’t help but have some sympathy for those who worry about this happening in their local (Admittedly, in my case, it’s watching a town where the suburban drops off to rural slowly be subsumed by city sprawl, so this might be a false equivalance).
But I think the real issue is that that’s not an evenly distributed 11%. People will naturally bunch up in groups along cultural lines. I could see a city developing a single Arab/Muslim neighborhood over the course of a decade being of no note, but it sounds like some are developing multiple over just a couple years.
I have no real data to back that notion up, but from what I hear from Europeans, that’s the general feel. I think that’s the real issue: things are changing and they feel like they’re changing fast, and that’s freaking people out. Telling people who feel that way they’re crazy only “others” them and I feel that’s really how the situation gets worse.
But also, the towns the guy above mentioned feel like bigger cities (I’m American and haven’t been to Europe, so I also might lack perspective), and so I do feel like they’re overstating the point.