Caste does not go away if you convert to an Abrahamic religion.
Asian christians pray in separate churches and are buried in separate cemeteries from White Europeans.
Non-black christians/muslims/jews have a history of treating their black counterparts very differently.
I can only speak to my own experience and this is not mine.
that's not due to some artificial separation like caste...
it's something to do with homesickness/cultural/language-related natural phenomenon. (eg. church pastor is a friend of a relative etc)
and no one thinks one is above the other due to the separation. (except for cooking...)
and conclude that people just regulary kill other people just because they feel like it...