You simply can not treat children as adults nor can all family situations be adapted to yield the necessary love & care required to raise a non-bully. Biologically, children also don't have the same ability to morally reason and weigh present actions against future consequences. There's also a good deal of evidence which suggests some personalities and brains have a preternatural inclination towards aggressive actions and violence.
Children also learn, nearly from birth, how to please their parents and will often, as the author did, shield their "shame" at being bullied.
I was taught by my father, quite simply, to "always stand up for your rights" and that "dignity itself is worth fighting for".
As a kid, I never started a fight, but I ALWAYS responded to violence with violence. For many bullies, violence is really is the only social interchange they understand and the attention they receive from the public physical domination of others is their main source of self-esteem.
I got into my fair share of physical altercations (which I lost more than I won) and subsequent interactions with school disciplinary actions.
Nevertheless, win or lose, I never regretted any fight as they were 100% effective at preventing future bullying.
If a bully "gets bullied back", they back down. If a bully "wins a fight", they know you're always ready to throw-down and take the full measure of consequences so they move on to easier "prey".
School systems are different, but at least in my case, it always helped out with the school authorities to have the higher GPA and be recognized socially as the "good kid that got in trouble".
Finally, one learns at a visceral level, the numerous costs and few benefits of violence. Violence becomes a viable option, internalized very concretely, as the option of absolute last resort.