Wow, that article is really one sided. Even if I accept the fact that it's all true, the teacher perspective doesn't seem to consider the parents perspective at all.
Teachers really don't know the kids as well as the parents do. This isn't the teachers fault, its because they're having to control 20 kids at once. Still, I've noticed as a volunteer many times where children have gotten reprimanded for doing something by one teacher when they were only following directions given by another. Because these children really cannot stand up for themselves, often times they don't know how to respond which can result in a number of different behaviors.
The burden of maturity should be falling on the adults (teachers and parents), not the children and yet so often its the children who respond in the most mature way.
Yes parents should not be so defensive when discussing their children with teachers, but at the same time those parents SHOULD be the advocate for their child who does not yet know how (or have the power to) to stand up for themselves.