Well, it's all driven by gross economic inequality, isn't it? Maybe certain people in this world, certain populations, are getting way too big a piece of the pie. As long as that situation endures you will see this kind of emigration of poor and desperate people to more affluent areas. It's always been that way, and it always will be. The only way you can calm a society down and create harmony and peace is by ensuring that there are not a great many people "on the outside looking in" (in the sense of their material well-being).

Or you can just kill everyone you don't like...and establish a new Nazi death camp system.

I prefer the former approach. That's why I'm basically a socialist, philosophically speaking. I do not believe in a society based on cutthroat competition, division into the few rich and the many poor, and survival of the fittest (meaning, the riches and most well-armed and ruthless). I envision society as a family, not a jungle. In a family everyone gets properly fed and housed and gets full medical care at no charge. That's brotherhood.