As a parent, you don't start your child at a school with suspicion in your eyes, with fight in your heart.
You arrive humble and hopeful.
You are let down.
You spend a while trying to get to the bottom of why and you are told to trust the school.
You try.
You are let down again.
You raise it and are lied to.
Rinse and repeat for several years whilst that gap between your child and their peers increases and is blamed on their disability.
A sense of hurt and sadness hits you with regards to your bad luck so you seek out others with children like yours. And you hear your story back at you, often worse. And then again, and again.
And so you ask reasonable teachers on an internet forum 'why? why do you do this?'
And they reply 'You can't expect us to adhere to the law, that would be ridiculous!'.