Some excellent points there by both Anthony and Flaps. Both highlight the fact that everyone has an input to Flight Safety.
Everything in aviation has a direct effect upon safety.
To highlight Anthony's points, I know of one organisation where the CEO's only demand when they wanted to recruit more cabin crew was that they be blond and big-busted. He cared not a jot about previous experience (one ex-BA girl, flying for 10 years, was edged out because she highlighted various safety concerns).
You simply cannot take a school-leaver, point out the first-aid kit and the extinguisher, and let them fly the line on day 2.
Yes, you may get away with it. People do, every day. But you cannot be in total control of every other aspect of the flight. And sooner or later, something is going to go ping and people are not going to be able to cope. Eroded safety margins will tell and, in an incident which previously might have claimed merely a few shattered nerves, an accident will develop which claims the lives of all on board.
Those of us who put our lives on the line need to dig our heels in and stop those that don't, and don't understand or accept the inherent dangers, from further endangering us, our colleagues, our families' futures, our aircraft and passengers.
As it says - "Flying in itself is not inherently dangerous. But, to an even greater extent than the sea, it is very unforgiving of any carelessness, incapacity or neglect."