F3G - Thanks, an interesting link.
The fact remains that this is a word that I have never heard used outside the confines of PPRuNe, and within, rarely. If the usage was widespread, then I agree that an issue might exist.
It is for the reasons covered in your link that I prefer to use the phrase 'customer' when discussing people on the aircraft: It re-enforces the view that there is a financial transaction behind each seat occupied.
It is worth noting that some people dislike being referred to as 'customers' on board the aircraft.