In addition to writing style and the question being very broad, I think a lot of the negative reception also had to do with the assumption that a passenger with no actual flight training would be useful to the flight crew of an airliner. It's roughly comparable to asking "When a patient starts having complications during spinal surgery, how can a hospital visitor who has surgery experience from playing Operation enter the operating room to help the neurosurgeons?" The answer, of course, being that they can't because they'd have no idea what's going on and they'd be a distraction to the highly-trained people who are trying to figure out what's going on and fix it.
In the case of AF447, it's unlikely that the passengers even had much idea that something was wrong prior to impacting the water. Even a trained pilot probably wouldn't have known that anything serious was going on unless they happened to be monitoring a GPS unit at the time.
Asking if a passenger could be useful to the flight crew in a specific type of emergency probably would have been better received, since it's specific and doesn't start with the assumption that the passenger actually would be useful. Making the assumption that someone with no training would be able to fix a problem that people with several years of training couldn't comes across as arrogant, though.
By the way, I hope this answer does not come across as being offensive. No offense is intended. I'm just trying to give an honest assessment of why I think that question was not received well.