They're not to blame. The problem is that usually the countries, in this case, France, build something like ghetos where the emigrants lived. Ugly places where children grew away from the others in almost closed communities. Parents were away, working all day and they stopped school very early. There was always, also, a lot of racism. Emigrants also didn't try to integrate and build those communities where they lived as in their homeland and spending the less they could to take the money to their homeland. Now France is seeing the errors but it's to late and there's a great hate from the Arabians against the government.