Inattentiveness is not ADHD. Being overactive is not ADHD.
And he's right in this: It's not one disorder; it's a syndrome or a variety of syndromes if you want to take the different collections of symptoms as different syndromes. Throw in a little sensory processing disorder, and you have my younger son. He is, as we say back home, wicked smart, but he's challenging in many ways. And it's not about lack of priority, television, or videogames, not that 'Stang would suggest that to me. It's the way his brain works. It ain't the same as how the other one's brain works. He takes supplements, does karate, and does OT (with various strategies that come with that). My wife brings up meds once in a while; we argue. I am NOT in favor. We must find other ways to help this kid, and then to help him help himself as he grows up. It's hard for him to negotiate physical space, attentiveness, and social interaction. None of that means he's lazy, dumb, or hyper, or that we are bad parents.
All that said, yes, it is overdiagnosed, just as we overcode in special ed. But the "It doesn't exist" rhetoric is not helpful. It's not even honest engagement with a problem. And it's not necessary straight talk or tough love. It's just dismissive and divisive.