http://www.google.com/search?hl=en&q=black+social+networ...
http://www.google.com/search?hl=en&q=muslim+social+netwo...
http://www.google.com/search?sourceid=chrome&ie=UTF-8...
http://www.google.com/search?hl=en&q=arabic+social+netwo...
http://www.google.com/search?hl=en&q=black+social+networ...
http://www.google.com/search?hl=en&q=muslim+social+netwo...
http://www.google.com/search?sourceid=chrome&ie=UTF-8...
http://www.google.com/search?hl=en&q=arabic+social+netwo...
EDIT: This star trek episode comes to mind (Are you blind?): http://www.youtube.com/watch?v=vi7QQ5pO7_A
Caste is just another uneducated, thoughtless distinction to discriminate against other people.
Caste is as correlated with cultural identity and upbringing in India as religion, nationality, and skin color are in other parts of the world.
- You should ask KKK/Neo Nazis if they consider Blacks inferior or superior?
- You should ask Chinese if they consider the mixed race Black singer (from the Chinese version of American Idol) inferior?
- Some Muslims consider non-muslims Kafir.
- Shia and Sunni consider each other inferior.
- Some muslim sects in Pakistan, and elsewhere, are considered non-muslims.
- Jews consider Palestinians, and vice versa, inferior.
And so on and so forth...
So, yes, those examples do apply.
My point is that this is one more manifestation of an inherent feature of human behavior, to consider similar people to be better than dissimilar people. Societies that become prosperous and educated can counteract this urge to some extent, but I haven't seen any society that really stamps it out.