I actually can't say I'm surprised. I've talked to a number of African businessmen who've spent time traveling and working in India on business, and they report that the discrimination and bigotry they faced there is a real cause for concern. One of the weird things about racism is that it's not just former colonial powers/white people discriminating against BIPOC, but also a vast complicated web of xenophobia that some POC exhibit towards other POC. There is a historically discriminated-against ethnic group in Afghanistan who have been persecuted by the Tajik and Pashtun majority, because they look Mongolian/Central Asian and are not Sunni [1].

[1] https://en.wikipedia.org/wiki/Hazaras

I have personally seen discrimination in Pakistan, by the ruling elite class in the Islamabad/Lahore area, against darker skinned persons of different ethnic groups whose home area is in Balochistan.

I think it's good to be reminded that "POC" is a very coarsely-defined term that comprises a bunch of different groups, some of whom can be racist against other POC groups. Racism, even of the systematic kind, is not limited to white people oppressing non-white people.

It just goes to show you that people like having power over other people, and they'll find any excuse possible to turn some group into the "other" so they can feel justified in oppressing them. In the case of the Indian caste system, race isn't required for this. In Afghanistan, as you point out, it can have a big religious component (though race is part of it too).

It is interesting to note that systematic racism against white people doesn't seem that common, at least in places I've visited (mostly Asia), where white people are in the minority. Discrimination there seems to be more xenophobia-based than race-based.