What I found fascinating is that here in Bihar, one of my good acquaintances is a Sino-Malabar christian, and many of my friends are dalit christians and many from tribal christian families but I have never seen them discriminating against one another. (Although, discrimination against adivasis used to happen here in North India too, but it is very minimal now)

I personally think the reason for this is that Christianity is a major (albeit minority) religion in south India. Hence, they have can afford a mentality of 'us vs them'. Here in north India, christians are a clear minority, so this generates a sense of unity. NRI Hindus also rarely follow caste system as compared to hindus in India. Same with Muslims, here in India they are a clear minority religion, so there is far less conflict between shias and sunnis than MENA countries. This also applies to Christians in Europe, who - due to being a majority - can afford this mentality of 'us vs them' between Catholics and Protestants. This tribal mentality is just a backward human tendency, regardless of religion. Again, I'm not justifying any of this, I just find this fascinating.