I am not questioning the ADHD, but I can tell you this:
The child has "significant" behavorial problems that are not caused by ADHD
Children are not born "having" problems with anyone in authority, they learn it.
Children are not born, with lashing out violently at people, children or whomever, they learn it.
Children are not born learning to handle their problems with violence, it is a learned behavior, which if not corrected with proper discipline methods, then that is how they conduct their lives.
I am sure this is not the first time this child has "displayed" her violence, I would put money that the school has tried other methods, to no avail. Obviously this girl just does "not get it" but maybe now she will as there are more serious consequences to her "actions".
It is not like her behavoir will get better over time........that "suddenly" the core personality traits will change and her behavoir will change for the better. It is not the schools job to co-parent the child.
The child's is now in school, now the "child" problems of ineffective or indifferent parenting are now the "schools problem, the educational systems problems, the teachers problems and now the other students problems. Actually now the problem of society.
If there is a child that has a problems with authority, reacts violently to any perceived sense of injustice, demands immediately resolution to her problems, is violent, lashing out in anger, then I can say without a doubt that this child now and as she grows older will have involvement with the criminal justice system.
Who knows what she will do at eight, 10, 12, 14, 16.
Let hope her next "assault" is only a teacher and not another student.
Or she feels "threatened" because the teachers in "authority" are making her do something that she does not want to do. Or someone else, like a Police Officer or a supervisor at her job.
Lets hope she does not bring "a readily" available gun to school at age 11 or 12 and do a Columbine.
Because after all she feels like the school and students are "unfair" to her and that "she feels a sense of a perceived slight" that she is angry at the school and students.......
With my kids, I won't let any of them "blame" the pets or anyone else for their conduct or behavoir. I hold them all responsible, accountable and with the appropriate consequences for their conduct.
That is just how life and society works.......