It's a great question for Meta.
I think the best answer is to approach each question with an attitude of,
"How can we be as helpful as possible?"
Knowing when to ask "What have you tried?"
We are not here to chastise anybody, so asking, "What have you tried?" is fair to ask if the intention is to get information that helps to clarify the question or provide a better answer.
Asking questions at the outset of an endeavour is just fine - and often a very smart approach.
The basic tenets of Free Software's Four Freedoms is to use, study, share and improve software. Joomla! was founded with that in mind.
Joomlers have a tremendous amount of knowledge and insight - and Joomla SE allows for anybody to quickly scan and answer questions - if a question is not well-formed or researched, you can choose to skip it entirely or to provide some guidance and assistance.
Keep in mind also that the goals of open-source communities are not so much to learn 'self-sufficiency,' but to provide an 'opportunity to collectively learn from others.'
...and how many times do we say, "Don't re-invented the wheel!"
For many, figuring out solutions collectively - and helping each other (often complete strangers) - is one of the greatest joys that involvement with an open-source project can provide.
This is a markedly different circumstance than, for example, a junior programmer in a company constantly consuming the time and energy of their co-workers and superiors because they lack the tenacity to research and solve problems on their own - instead, we provide a space that is conducive to co-operative learning.
One of the greatest advantages of Joomla! is that you don't have to be afraid to ask!
Being too Needy: Knowing when to be self-sufficient and knowing when to ask for help.
Where is the exact line between spending enough time researching a problem and knowing when to ask for help? I do not know and I doubt anybody can provide a definitive answer.
I think this is different for everybody and a self-learned skill - and I am convinced it comes down to self-confidence. Build up people's self-confidence, and they will automagically become more self-sufficient - they will even want to help others!
Also, from personal experience, when I need help, often the key problem is that I don't even know what the right questions to ask are! (Once I find I'm asking the right questions, the answers are easy to find).
"Have you tried...?" (a slight variation of "What have you tried?") is a great question to ask because it will often help people figure out that there may be solutions and approaches to their problems that they haven't even thought to consider.
It will not only help that person, but others researching the same problems.
We are all ambassadors of Joomla!
Most of all, we are all ambassadors of the Joomla! Project. Good diplomacy dictates that we should strive to create as positive experience as possible.
In this sense, it doesn't matter so much what somebody has tried (that's the past), but how we help them on their journey (the present and future).
is the site intended to house answers for non-developer Joomla users at all?
Of course! Why not? Everybody starts somewhere - and think of how 'snooty' and what bad ambassadors we'd be if we excluded non-community members from Joomla SE.
I like to think that the Joomla! Project will, in someway, be responsible for many people who've never coded to get inspired to become 'full-stack' developers - and even core-contributors!
That first-step may likely start here.