should country promote migration?

What people? What migration? If you mean the smart ones who are believing in taking risk for high return, they are welcome. Even in Europe, it has begun to issue the green cards.I'm not kidding.Asking an Indian nationality near you.But if you mean unskilled people who are regarded in the US as Gold Digger, they are not welcome, but still come in anyway.The US economists suggest the European to open the border for labor migration to save the Euro on the framework of optimal currency area. The European still fall on deaf ears.But the Euro get more stronger everyday.

Sure! Get RID of people who hate Capitolism!

It depends on which country you are thinking about. You don't say.

Mexico already promotes illegal immigration into the US. Because their economics are so poor, and the Mexicans send money back to their relatives. There was one study that said like 12% of Mexico's GDP is money sent back to relatives.