Joe my good fellow,
I don't think (in my glenmorangie addled mind) that the majority believe that adversity is a rite of passage. A person only truly remembers the good things of their past, not the more abhorrent parts, with some exceptions. When the ones on here speak of 'doing the hard yards', I do not think they remember how it felt thinking they may never make it as a CPL, struggling for that first job, let alone the first twin.
What I think some take umbridge with is the payment that takes place. Most of the ladies and gents who experienced the 'adversity' you speak of, had to put themselves through flying school, whilst still supporting themselves through everyday life. Now when you compare that to a cadet scheme in which the cadet must fund it by their own means (or 'other' means) in addition to support themselves (or being supported) during the 9+ months of a fulltime cadetship, we now come to the core of the 'umbridge'. The above situation essential means a select few young hopefuls (read silvertails) are really the only candidates elligible for said cadetship. This in turn, financially excludes a great deal of what may otherwise be very good candidates.
If these programs were a fully funded scholarship situation (therefore levelling the playing field), I think the 'umbridge' would be considerably less. At present, not even Australia's national flag carrier does this.
However, the above is only in my addled mind, feel free to disregard as you see fit.
Straight home and don't spare the horses