I was quite offended to learn about the post-WWII European migration policy through the decolonization period of 1945-1962. Wait for it; it starts okay, and gets much worse.
After WWII Europe experienced labor shortages and a pressing need for working hands to rebuild all those destroyed cities. The governments of Germany, France, the Netherlands, etc., the solution that they came up with was to bring over "Gastarbeiter," i.e. guest workers, whom they falsely expected to stay only temporarily. The workers came from nearby (former) colonies: Morocco, Algeria, Turkey, etc.
At least in the Netherlands, it was under the initiative of the labor party that agencies were set up in the Maghreb, i.e. Northwest Africa. Their task was to find potential immigrant workers who were not only the least skilled but also the least likely to *become* skilled, least likely to achieve social mobility in Europe and to take up anything *other* than unskilled manual labor. Preference was given to the least educated, the least "intellectually promising" -- people who hadn't completed high school education, people who didn't know any second language besides their native Arabic/Turkish, etc.
Upon arriving in Europe, the immigrant workers were cast adrift to await their fate. No serious efforts were made to accommodate them, integrate them or help them find their place in the new society in any way. The result today is that there are vast isolated communities in Europe, ghettos, ethnic enclaves, cut off from the mainstream of society, impoverished, uneducated, socially immobile, and prone to radicalization -- usually all the wrong kinds of radicalization.
(It might be worth noting here that while this is typically true of the socioeconomic origins of Turks and Northwest Africans in Europe, the opposite is true of the Iranian diaspora, as it was the "cream of society" that fled Iran in the aftermath of the Islamic counterrevolution, in one of the greatest brain drains of recent history.)
* * *
So here's my follow-up question. In such situations, what is in the interests of the global proletariat? Should the native European workers have supported the policy of unskilled immigration, or a policy of skilled immigration, or an indiscriminate policy of immigration whether skilled or unskilled (up to open borders), or a policy of strong restrictions on all types of immigration? Should native Europeans, workers in particular, have demanded more of the government and done more in their communities to accommodate the foreigners, guide them, and encourage them to participate more actively in society, to unionize and organize in general?