I am also amazed at people keeping up or bothering with people they hated at school.
There are obviously some sad experiences on this thread but I would Blame the bullying policies and ethos of the schools rather than the children.
Swiss your school was a selective grammar?
Maybe the selective/independent schools foster the competitive ethos and superior attitude that almost encourage the queen bee types.
All I can go on are my childrens experiences and that of their friends.
The ones at in dependant and grammar schools are constantly complaining of nasty behaviour like this and the teens attending often tend to be very immature and so less empathetic.
At my kids huge comp there are far too many mixes of kids for one group to dominate. It wouldn't be allowed anyway as the kids themselves seem far more mature. Yes there are kids from hard backgrounds and some from wealthy homes but all manage to shake down.
Brains and looks are not key! Trust me in both my dds groups and in my dss in their time there were all types, classes, abilities and looks.
I really do think this abounds in the selective schools.
In my kids schools anyone starting that malarkey would simply have their head pushed down the toilet. The bullies are policed and dealt with.
In point that vile girl who featured on the fb bully thread lives fairly near to us.
The reaction of the teenagers at my dds school was horror anger and disgust.
It also helps there are CCTV cameras in all corners probably unlike most old venerable schools. 