There is the XY problem, where a solution for X is wanted, but a question about Y is asked.
I think there's also the problem of the assumed XY problem, where a question about Y is asked, but X is assumed.
While the question may be specific, instead of providing possible answers, the people defaulting to assume the XY problem want to figure out X and either reproach the asker and/or require details about the assumed X that are likely not needed to answer Y ("tell us what you are really trying to do or we can't help you").
I think SE's platform with it's focus on very specific issues and answers limits the issue, while forum discussions can easily lose focus on the original question and extend to other aspects of the (assumed / underlying) problem.
How is this motivated? Do people
- genuinely want to help, and assume the asker really wants help with X?
- assume they "know better" that what is being asked is not the actual question (arrogance)?
- find Y is too easy (boring) / see a better challenge in finding/solving an underlying X (achieve more "rep")?
- like to point out there is such thing as the XY problem to show they are more knowledgeable, but do not actually intend to help with either Y nor X?
Is there a name for this "opposite" as well? How can people assuming there's an X to the Y be convinced otherwise?