IME some teachers fancy themselves as 'outreach', helping those poor little disabled children and their retched parents.
Children without advocates are attractive, especially as there is then no-one to be accountable to. Teachers can work tirelessly to try and get the parents on board, to impart their expertise, to flaunt their 'professional opinion'.
When a parent comes along saying 'hang on a sec, why are you doing it that way, - I'd like to see some outcomes', teachers slam their doors shut.