European (and American) leftists have successfully relegated common sense to the far-right fringe... it's past time to ostracize the far lefties and let common sense reign again.
"suggesting that the minorities themselves are not doing enough to adapt to European mores."
My common sense says that if you relegate certain groups to closely confined quarters, such as housing projects, the only thing you manage to do is pool pathologies. Everyone knows that if you want to change your lifestyle, you have to change your associations first of all. Since the French wanted the "youths" out of sight, out of mind. Since they set up a labor situation which effectively cuts out youth from integrating, since they maintain a national attitude of superiority and (evidently) scoff at people learning French, then it seems they have only themselves to blame for the lack of integration of their immigrants. (Not that Muslims need any encouragement to avoid integration but France has definitely made it easier for them to remain "apart".)
We need to learn some lessons from this. I don't think as a society here we should encourage immigrant clustering if we can avoid it. We should be setting the stage for the second generation immigrants to move into the mainstream/ I grew up next to an Indian Reservation. I remember a panel discussion in high school by some of the Indian students who said it was extremely difficult to not only leave the reservation (partly because of the benefits tied to reservation residence) but also to even start to integrate into mainstream society while still living on the reservation. Any Indian caught "acting white" was ostracized by the tribe. Even if they just used some of the BIA money to build themselves a decent house, it was enough to destroy their social standing in the tribe. The kids were strongly discouraged from participating in extra-curricular activities such as sports and clubs. It was sad and many of those same youths who spoke to us either committed suicide or ended up in jail. I can think of only one who actually escaped the tribal trap, or at least I think she did. It has been many years since I have lived there.
The point is, you need a welcoming society and support from immigrant (or native) elders to really integrate. Our nation needs to start seriously integrating all immigrants and native Americans if we want to have a peaceful society in the future. (And without trying to stir up a hornet's nest, yes I favor abolishing the reservation system and sovereignty issues with Indian tribes.)