Earlier quoted context omitted.
I mean... like most spectrum disorders, most people experience and can relate to at least some of the core symptoms, even if they don't express the full spectrum or severity. So when someone says they feel like they have ADHD, they are probably not inaccurate.
How can someone say they have a disease or affliction while not understanding what exactly that affliction is as opposed to what they think it is/have been informed by media/society/non-professionals?
That generalizes all the way.
Everyone's just working off what they've experienced or what they think is true, for mental health or where to find good lunch.
There is no universal truth. Everything is moving relative to everything else. New year, new DSM.
It would be more surprising if our shared experience was more different than more the same.