Funny you mention heathens, heretics and kafirs. All of these are people who are non-believers in their corresponding religions. Dalits are actually believers in Hinduism. No other religion in the world discriminates against the very people who chose to adopt it, except Hinduism.
I'll reiterate, it's very rare in other religions and uncommon. Mostly remnants of Hinduism. But ask an average muslim or a christian his caste and he will say that he doesn't have one.
I'll reiterate, it's very rare in other religions and uncommon. Mostly remnants of Hinduism. But ask an average muslim or a christian his caste and he will say that he doesn't have one.