I would argue that no one gives more to charity than Westerners. However your situation is not the same as indirectly giving to charity of course.

It’s maybe a combination of how we (Ireland anyhow) are raised to react to someone asking us for money. I would perhaps think nothing of lending an amount under say £40 to a friend but anything more and I’m having to weigh up what can I spare and why would I?

How well do they really know you? Have you perhaps overvalued your relationship? Have they been the charitable type in the past? How well are they doing financially? If you had asked them outside the pandemic do you think they would have?

Now I have a, probably wrong, stereotype of a lot of Americans looking down on less fortunate people, the way the homeless are treated etc. Does that factor in? You say American and Irish classmates but I’m assuming that means Irish American?