> "Don't be a crybaby." "Shake it off." "Toughen up." "Words can't hurt you."

That is different issue. When kids are bullied, these are good for adults, because they force the victim to be silent, so that peace is kept. If you are educator and believe those, problem with bullying is essentially solved.

You don't have to deal with bullies themselves. You dont have to spend effort teaching bullied kid how to effectively set boundaries. You dont have to listen to yelling as the kid is trying to set boundaries for the first time and inevitably failing.

You dont have to do anything, except telling the bullied kid to shut up.