I think discussions of "obscurity" are always relative to the audience in question, so while I highly doubt caste discussions would reasonably be considered obscure in India (or within the Indian diaspora), I (a non-Indian) had certainly never heard of casteism abroad until I saw submissions on HN discussing it at Cisco.

Agreed. "Region specific" might be a better term for what the commenter intended

It's "obscure" bc it is underappreciated in the US and probably most places outside of India

I intended 'obscure' in the 'not easily understood' (to outsiders) sense, but probably an unfortunate word choice as it also means 'unknown'.