I forget what the concept is called, but I will call it something like emigrant conservatism, where emigrants bring essentially a snapshot of their culture from when they emigrate, and that snapshot remains fixed - they don't feel American, so they don't integrate into American cultural norms, and they don't have much active interaction with their previous home's culture which is constantly progressing.

Well. I am from an NIT in India and upper caste groupism is super common there. Of course to an outsider it seems like these are guys from the same high school and same hostel hanging out, but in reality it is mostly upper caste Brahmins in those high schools as well who end up continuing their groupism and favoritism in college and beyond. The same groupism exists even today - decades later. You see the same upper caste brahmins hanging out in the US together still in their close knit groups.

Either that is lack of awareness or a misrepresentation. Please have a look at this: https://theprint.in/opinion/brahmins-on-india-campuses-study... . There were lots of anecdotes about this going around. But it's documented news these days.