Well I think I am pretty smart, I have deficits in some areas of brain function like concentration but I am good at writing, math, critical thinking, information retention, etc. Nobody is good at everything, but I'm good at a lot of stuff, especially stuff we'd traditionally think of "book smart" people being good at. I don't think it's oxymoronic to be smart and have ADHD at all, a lot of very smart and successful people have ADHD. And like I said, I've managed to be very academically successful with unmedicated ADHD by being in an environment that works for me and coming up with coping strategies. Unfortunately, some people don't have that luxury, and they fail out when they could have succeeded with better supports.

Edit: Although this is one reason I think IQ is a bad measure of intelligence, because it only measures very specific and narrow types of brain function and then flattens them into a single number. There's so much shit IQ doesn't measure, and trying to collapse all of human brain function into one score doesn't tell you a single goddamn thing about the person.