The FACT it was flying below 500 feet, is!
"Fact" is that this is your personal opinion of the situation. Your personal opinion would not stand up in court, just as a personal opinion of a vehicle speeding needs other evidence.
The thing you're really not understanding is that you have declared yourself to be an expert, and take exception to those here who have quite rightly questioned you about this, but you will not back that up by information regarding your qualifications.
Folks have been around here long enough to have seen this sort of thing here before. Someone who will not give a straightforward answer to a straightforward question possibly has something to hide and therefore will understandably be treated with suspicion, if not derision.
You have your "victim". He has explained the situation from his point of view but because this does not fit your "facts" you now claim it was someone else.