It does however make her a shit parent for making excuses for her child's bullying instead of giving/getting said child the support he needs.
Just as some of you are saying "I'm sick of people excusing bullies" I would like to say I'm sick of people who cannot see that sometimes a CHILD and let's remember they are all children, a CHILD going through a hard time needs help. In the highlighted example above, no-one said that the bullying should be excused, or that the bully shouldn't be punished, or that the school shouldn't protect the victim first etc etc.
And no-one said that the parent was making excuses for their child. Quite the opposite, the child's behaviour changed, The family realised why and put in help for the child.
This isn't black and white as the quote from The Gulag nicely expresses.
When a child starts to behave in this way, as any child can, even the wonderfully empathetic children of super mothers. When a child begins to behave in this way, the issue is that they need intervention.
In a good school, this intervention happens quickly with the protection of the victim at the forefront, and their safety paramount. Then the bully is given the support and help they need to get past whatever has happened to them eg bereavement.
The issue in 99% of the stories above is the school, and how they intervened, or failed to. I have worked in amazing schools where it happended properly, and victim and bully had help and the bullying stopped.
There are some kids and parents who will never change and who are genuinely nasty, but there are many who are not, they are kids in crisis.