I think non-Indian Americans are shocked that this exists in America, and totally have no idea why this is even a thing. How can I discriminate based on somethi

I think non-Indian Americans are shocked that this exists in America, and totally have no idea why this is even a thing. How can I discriminate based on something I don't understand. My Indian best friend told me he's in the warrior caste, when I asked him about the caste system, but I have no idea the hierarchy or how someone would discriminate based upon it.