Do I have to explain why I need some code related advice? Do I need to explain why I don't want or can't use some technology or part of framework when in my question I specifically seek advice on correct way of coding my solution of my problem?
Let's say I try to write copy of STL and I need advice on some twisted generics voodoo. Do I need to explain why I just don't use STL and why am I reinventing a wheel? Do I need to explicitly say that it is just a learning experience or what are reasons behind my question? Because without it my question instead of valuable answers will be polluted with "you should use STL, reinventing a wheel is stupid" remarks.
What if I can't explain my reasons due to fact that I can't talk about my work in details? What if my STL is not in fact STL but something under non disclosure agreement but to make my problem more clear I use STL which is familiar to most of developers?
NDA is one of reasons why somebody may not be able to explain details but I understand critics about that point in my question.
That said if somebody asks about specific code and give you this code as example and visualization of his question do you really need to know why does he want to write this code? Maybe his boss is crazy and this is one of his crazy requirement? :)