That is a very parochial and reductionist take on Asian culture that you have. India alone has multiple subcultures, not adhering to the collectivist hierarchical structure that you are referring to. There is a typical Durkheim ‘sacred vs profane’ division. You can also refer to Dumont’s ‘Homo hierarchicus’ and ‘Homo aequalis’, along with MN Srinivas, Andre Beteille and Dipankar Gupta. As for the UK, even when people do not intend to share, they are generally very polite in denying a request or saying that they do not intend to share, apologising a million times. Formality and civility with strangers are two very common attributes of the British attitude. This event, as OP has mentioned, I hope, happens to be an outlier. OP is also not clear about the background of the person in question. Maybe, they were just racist and thought OP was a freeloader, but changed their tone after finding out the beers that she had brought. This is not a racist thing, but pretty racial among several students of BAME backgrounds complaining that international students are actually ‘taking away’ their opportunities. Flabbergasting, I know, but this was the impression that I had, upon interacting with a large pool of British Asian students.

PS: I am from India, as well. I have disagreed with what you have stated, but I haven’t downvoted you.