It makes a bigger impression that way, making people in Western countries more likely to accept dhimmitude.
I guess there was no obvious Jewish center, like the Chabad house in Bombay, available, or perhaps this group of "youths" wasn't as sophisticated.
It seems the further you get from Jerusalem, the more likely any Muslim is a target (for example, the problems on Mindanao in the Philippines).
Muslims see with 100% clarity that there can be no coexistence with non-Muslims; they will either win it all or lose it all. Only Westerners somewhat insulated from the threat sees it otherwise.