If someone with ADHD doesn’t understand why they should do something, they probably won’t do it.
They won’t accept “authority” or “because I said so” as valid reasons, which can be misread as Oppositional Defiant Disorder. They have no issue with “legitimate” authority - it just has to be earned & understood. It’s a desire to understand, not a sign of disrespect.
Often ADHDers have trouble connecting immediate tasks (do homework) to their why (graduate college). North Star-ing can be a helpful exercise for working backwards to determine the long-term goal of an action.