I think that this is just the first step. We're learning Sal and Marcie's shared history and why it is that, firstly, Marcie ends up speech-impaired, secondly, why Sal feels so protective towards her and, finally, why Sal hates authority so much.
If there's one thing I learned unequivocally at school it is that dealing with bullying is far too difficult a chore for most teachers to bother with. It's simpler to urge the victim to 'fight back' or 'ignore it' and, if it carries too long, refer them to a child psychologist for being a victim (you can tell that I'm still bitter about this nearly three decades later, can't you?).
I've got a feeling that this 'Leyland' creep is probably going to turn out to have a social shield too and that the Walkerton parents will support him and penalise Sal for embarrassing them by directing an accusation at a member of a socially prominent family.