Because for us Westerners this form of discrimination is, well, invisible. It is based on subtle things we don't see. It stays within a group, that to us, seems completely homogenous. Plus, how many Westerners actually are aware the Indian caste system exists at all?

men discriminating and harrassing women? Sexism, check.

White discriminating people of color? Racism, check.

One Indian being a dick to another Indian? A personal thing between those two people. Only that ot is not, it is so much more, we Westerners just don't see it. And since we don't see it we have a pretty solid chance of intervening on the wrong side, if we intervene at all.

I had another comment but deleted it.

Effectively, the idea was "Don't be a dick." That is a reason right there where a person can intervene if they are in a position to do so. However, the issue as you raise it is that this is not a law.

There are laws about sex, racism etc that can help people in low power situations exercise some power. But we don't have that equivalent knowledge/ability regarding caste.

Agree there is a ton of nuance, at vmw I didn't notice it till I heard about it, then I did, but like you said its really hard to know how to intervene