I don't think it has much to do with individualism/collectivism. A lot of people are worried about a lot of things beyond themselves; most eventually realize it's bad for mental health and grow out of it, some pick a cause or three and act to make things better, and then there's also the lot that signal worry because it makes them look good.

Of course this is a process, so especially with younger populations, you are going to meet a lot of people worrying about random issues big and small, because it takes time to process it and learn the coping strategies.