I guess cs is just more popular in eu. I would expect your ex classmates to play games like cod, halo etc, am I correct?
I went to an IT high school though so that's definitely one of the main reasons why there were so many cs players in my class. But idk, even in elementary school I swear the whole school was playing 1.6. We went to geography club (because it was in a class with computers) and just played 1.6 the whole time there lol, with kids aged 10-15.
As I said, I think it's kinda the same in NA but with different games like cod.