How is it racism to say India has a caste system and they've had a lot of practice? It has nothing to do with the colour of their skin (or whatever else you usu

How is it racism to say India has a caste system and they've had a lot of practice? It has nothing to do with the colour of their skin (or whatever else you usually base "race" on - I'm not from a culture that uses it like that so I don't understand fully), rather it's a given of the country.