John,
Your of course correct in saying that people receiving unsatisfactory answers should persist. But we must remember that many will inevitably be a bit reluctant to do so. Looking at all of the (what to many at that stage are ) unintelligible answers, it is easy for them to feel that the fault is theirs.
Sending the first post is always the most difficult. Far more students would get over this hurdle if they felt they were could expect to understand the answers they were likely to receive. I think this would best be achieved by a general improvement in the quality of answers, rather than expecting individual questioners to repeat their questions. If readers find they can understand and learn from the answers to questions that have been posted by others, they are far more likley to ask their own questions.
I also think that there is a wider problem which originates in some of the FTOs. During a consolidation course last week, I was discussing the question of whether lift is created by low presure over the wing, or by the downward acceleration of air. A student suddenly said " That makes perfect sense, but we could never have held that conversation with our ground school instructor. He would have simply accused us of being stupid." Students experiencing this type of treatment in the classroom are unlikely to be prepared to post a first question in pprune, let alone persist in repeating or rephrasing it when unsatisfied with the answers.
Finally, I can see that I have now allowed myself to make what I consider to be another very common pprune mistake. This string
started with a question about V1, VR and VMCG. We have moved on to a totally different subject without first ensuring that the originator is satisfied with the answers he has received. Only DECU can answer that question...........