I don't think that behavior should be called anti-social. Why do you put their online friends in quotes? When I grew up, I only had one real friend, and everyone else I played with only because they lived on the same street. I did not particularly like the games most of the time, but there was no choice.

In contrast, these kids have friends, who actually share some common interest. They choose those friends. And also, probably, more of them. If anything, I'd call that hyper-social.