We've all heard the misinformation tropes "Back in my day, a kid was hyper because he wanted to play, nowadays $BOGEYMAN says those kids need to be medicated so they can get a 4.0", and they sound so alluring to large groups of people, so they write off ADHD altogether. Yet I distinctly remember kids from my childhood who could not hold a conversation, they would literally break off into a new topic while you were mid-sentence with them. Tell me how that kid can possibly learn anything if he doesn't even know that he vacated a conversation.
This is a parallel to George Carlin's "It's called shell-shock" spiel, or used by people to deny the existence of depression. It's very difficult to both convey nuance, and get people to accept it, even though it (the nuance) abuts life-threatening issues.