ADHD is a real biological disorder, that is a medical fact. Meds are just another tool to help address the issue. I’m not going to explain or argue about biology.
Can people’s personalities contribute to their problems? Yes absolutely, nobody is arguing that. You’re not wrong about the usefulness of therapy , but that’s a pretty dismissive and rude way to go about it. Nobody here is saying therapy isn’t helpful.
It seems like you just want to pick an imaginary fight with people who are just looking to find a path to improving themselves.
Its a catch all diagnosis for underdeveloped executive functioning. The biology you are talking about is a description of a neurological state.
It does not mean it cannot be developed. It is underdeveloped due to prefrontal cortical issues pertaining to early life experiences which shaped the personality. This is absolutely something thay can be changed.