@rama Welcome to Fluther. Great question.
I’m not sure where you live on Earth, but here in the USA we’ve been struggling with social integration since our nation’s inception and even before, when we were just a collection of colonies under the authority of the British Crown. We are far from having it right as of yet. We work on it daily. We often fail. But we are progressing.
@Bill1939 has a great point about it being human nature to prefer to be with others similar to us. We evolved as a social animal, and like all other social animals, we were and still are to some degree tribal. But we now live in an age where jet travel, high speed trains, automobiles, and ships allow for the constant mixing of cultures. We beam TV shows up to satellites circling the Earth, and then back down to TV sets on the far corners of the globe. The Internet connects all but those in paranoid nations like North Korea. We clearly are on the way to abandoning our tribalism, and becoming a global village.
This makes some, particularly those with strong, authoritarian beliefs, exceedingly uncomfortable. Stick to your own kind, they will tell their children. They will instill fear of otherness in their offspring. They will fight the progress of social integration till it eventually subsumes them or their fear of it leads them to trigger a global nuclear conflagration.
I certainly hope those of us who realize that otherness is not a deadly threat to me’ness can ease the authoritarians into an understanding of the changing world, because once the technological genie is out of the bottle, we aren’t likely to succeed in putting it back in.