With regard to PW and flying, only dealing with rich white folk, and only having professionally based/centred conversations, no I'm afraid your point does not still stand.
If he went through the flying training system in a manner similar to previous royals (and it is reported he did) then he'll have for example spent time in the students crew room, away from the instructors and the senior ranks.
Nobody stands on ceremony in those places..it's a location where the students are either about how their last trip went or whose turn it is to clean up the coffee cups, and at time a place for comparing notes with other students on the next exercise, next instructor etc, or failing that discussing what happened in the football last night....
Similarly in the Air Ambulance work...he'll probably have been given short shrift by fellow crew and other team members if every single communication (either about something professional or something social) had to be handled on "remember you are talking to royal" basis, and (like in flying training) he will certainly have had to have been able to accept criticism and hopefully constructive advice.
Ultimately PW may well have his faults but certainly won't have spent all his formative years in a rich white person bubble, only taking time to communicate with the plebs about professional matters.