This is just my experience. But I can point you to handful folks from my circle whose friendship worthiness depends on belonging to one of the "dominant caste". In fact, I can also share an anecdote when person A was really fond of person B since B had last name that sounded like one of "dominant caste" last names. Once person A came to know the subtle difference in person B's last name, there was noticeable behavior change in person A.