Times have changed, immigration, legal and illegal is a fact of life.
America's borders are under pressure as are European borders.
With decolonisation, a lot of former colonies have fallen into conflict and corruption, the inhabitants of these failed states want something better, so its natural that they will be drawn to what they see as the centres of power and wealth.
Unlike in the past, even in the poorest parts of the planet, people have access to the Internet and television and they can see how the other half live, so they decide that they too would like to be part of this other world.