That's reasonable if you've only ever come across castes in this context. When I think of American buses, I think of Rosa Parks and racism, because that's the only context I have - but that doesn't make that the only relevant characteristic of them.

We here in India hear the "caste as abhorrent discrimination" side from a very early age (and that's certainly important), but it's taken me years of experience to learn that in practice it's more than that. People think of caste as a form of extended family, or as shared culture, or of understanding someone's roots. That person might have said that just as someone might say "I can't figure out if their accent is from New York or New Jersey": that might be an intent to discriminate, but might also well be idle curiosity about the person.

To be honest, no, that just sounds like you're doubling down on preserving harmful social structures because it benefits your in group. White supremacist groups in the US also focus on the positives and shared culture of white America. Hating blacks isn't the core belief, it's just a side effect of wanting everyone to know that whites are the best.

I don't mean to say it's hateful to say you want social castes out on the table for identifying who you share connections with, but that obviously comes with the fact that you identify those who don't share that connection. It's a justification for extending social problems.