Or middle class children with behavior that annoys their parents.

Well, it's both that and a legitimate medical condition. The problem is that the medication that works for ADHD also works for suppressing childish behavior that authority figures find annoying. Everyone involved are fallible humans that respond to incentives, and often the incentives align for teachers, parents, and psychiatrists to medicate children into compliance.

Or kids who actually have a problem. ADHD is not only hyper activity. Many have an attention disorder with no hyper activity issue.

Actually those are the most at risk because they seldom stand out or are called out for having a problem ,except with their grades.