I'm lost. Which pilots?
Aren't they just running a lear about with bit of planes and crew in? Bits for their own planes? Pilots who are their own staff? Why would being on an AOC improve the safety of that bit of the operation? And it might be stating the obvious but they do already have an AOC if there was a need. Sticking the lear on the AOC just adds a load of bureaucratic nonsense to what will only ever be a private operation. Holding an AOC is not a shield of invincibility - commitment to genuinely good CRM, flying ability, technical competence and not employing idiots is the key to safety.
I've never worked for Ryanair but I know quite a few who do and it always seems to me that the stone throwing is from the outside - those that work there seem to like it!