Europe didn't need American tutelage to open the doors to mass migration.
It opened the doors itself, in virtually all cases out of greed. Postwar, they needed the migrants to man the factories, as in, for example, Belgium, never thinking ahead to the fact that someday the factories might have to downsize, but the migrants might still be there.
Or, additionally, in the case of France, they got used to benefiting from the "colonial tax" to which 14 countries in Africa are subject.
Until the European countries see their history objectively, taking the blame for their own decisions, nothing will change.
France believed that telling their North African and SSA migrants in the name of liberte, egalite, fraternite, that they were now French would make these people loyal to France. There's a video making the rounds on twitter of journalists asking the French born North African and SSA teenagers if they feel French, and the resounding answer was "NO". One even said, you keep telling us we're French now, but we speak Arabic at home, we eat North African foods, our furnishings aren't European, we don't have European customs, even when we look at you we see we're not French.
That is emphatically NOT the attitude of the descendants of the great migration to the U.S. It IS the attitude of some African Americans, but by no means all, and, to point out the obvious, the coming of SSA people to American shores began before there WAS a United States of America, and it was NOT a migration. It was the purchase of human beings as slaves, human beings captured and sold, btw, by their own compatriots in Africa. We are paying the price for that decision based in greed, and Europeans are paying their own price. They should own it, as we own ours.