I've been thinking about this issue. The biggest problem with answering a
question with a question rather than providing an answer is that within the
NG format, a question has decreasing chance of being answered the longer the
thread goes on. The reasons are several. For one, with a busy NG, the
question is moved down the list fast and disappears from sight. For another,
there is an attempt by MVPs to respond to every question; but once a
question has been responded to by someone, it gets less attention; people go
on to newer, unanswered questions.
Getting a "Why do you want to do this response is frustrating because people
asking questions are often need a quick response. A "Why do you want to do
that" response can delay the needed answer for hours or even days.
IOW, the NG would be much more responsive if people actually answered
questions along with advice.
My suggestion then is that unless there's a policy reason not to answer a
question ("Hey guys, how can I cirumvent Microsoft licensing?"), answer the
question as best we can ALONG with the attempts to enlighten?