Most people simply cannot understand or relate to the challenges of the non-neurotypical, including the highly variable ADHD.
I had a challenging childhood and was thought by many to be a bad kid. I was precocious and acted out, because I was bored with school. Eventually got a PhD in my 30's, but was NEVER a good student, at least beyond age 11 or so. I always thought it was laziness or something was wrong with me morally / spiritually, but realized there was a lot of boredom and 'potential' for success when my intellect was applied appropriately. This whole time it was ADD, inattentive type.
In retrospect, I sure wish I would have known about this 30 years ago (I am in my 60s now). But knowing the why helps me understand my history and who I have become, even if others don't get it. Nowadays there is enough known about the condition that more are able to get the early assistance needed for ultimate success, but ADHD was not 'a thing' when I was a kid....
Those who are challenged by ADHD understand one another more so than the neurotypicals, we have the realization that we are wired a bit differently.