They have terminology for this in sociology. There's different reasons why, but not so many.
Most of it is due to adhering to old cultural stipulations and norms, the rest are lumped as forms of racism or however you want to view it as.
A few I can remember are..
The
Continuity Theory - basically that older adults will stick within their tradition and norms as they did earlier in their life, and pass these down to their children
Continuity Theory - Wikipedia, the free encyclopedia
Xenophobia - you've probably seen this before, just plain simple fear of non-native people.
Xenophobia - Wikipedia, the free encyclopedia
Social identities Theory - This is how we subconsciously categorize people in our head. Like the word FOB, rednecks, goths, hillbillies, deaf, hearing etc. We note the differences between the groups and distinguish them by stereotypical traits they do.
Social identity - Wikipedia, the free encyclopedia
The younger generation of this era is less likely to stick with these forms of stereotyped bias. It is subjective to how they are raised and view life, mostly from the traditions their parents, friends, social networks are teaching them.
Overall, sometime in the future the world will eventually adopt to an assimilated view where all races might even become mixed, but the "elitists" will always be around, even if just a minority in the future.