It sounds like you just wish they were more like you? Isn't this the kind of mentality that prevents diversity?
I actually hate when teams go to pubs because it just marginalizes people who can't/don't drink, god forbid there are any recovering alcoholics or people allergic to it.
While I can understand the frustration, I feel like you are in a position to get people to come together and feel more comraderie. After all, if these people are coming from other countries, their English is probably not that great, and it's likely difficult for them to communicate what they are thinking. I can see how they would want to go home and be able to speak in their native tongue, not to mention enjoy the things they used to.
It's our job to make them feel welcome and like they can express themselves in this country. Of course that's just my opinion and I'll admit I'm biased because I feel like I'm usually the one who doesn't fit in.