Do you think it's a coincedence that the boy is Jewish?

No, I believe the novel is making a specific point. By making the victim anonymous and removed from the main characters’ social circle, Strasser recreates the conditions that led to the Holocaust. Many average Germans did not have Jewish friends or acquaintances, so it was easier for them to distance themselves from the violence. It also underscores the differences between the main characters. David brushes off the beating because he didn’t know the victim, while Laurie and her family are very upset about it. This parallels the couple’s reaction to the Nazi film at the beginning of the book. David is able to shrug it off and enjoy his lunch, while Laurie remains disturbed for the rest of the day.

no way