A lot of what you say is true, the industry is greedy and all about the money, but you seem to be missing a few facts here.
Aer Lingus pays it's pilots a set salary. They're not paid per hour so for Aer Lingus having an oversupply of pilots is a bad thing. Aer Lingus pilots are pushed right up to the 900 hour limit and they only employ as many pilots as they need, not like other airlines that make a profit simply out of hiring pilots and it doesn't cost them a cent to keep them on the payroll.
This has nothing to do with keeping FTOs in business. The FTO has not been selected yet. Aer Lingus is the the business of making money for Aer Lingus, not for keeping FTOs in business.
This is Aer Lingus taking an admission based approach to the industry once again, it's training those that it wants, no more, no less.
You seem to be confusing Aer Lingus and FTOs a lot in your argument. This is not a whim Aer Lingus are acting on, they're putting substantial quantities of money into training it's future pilots, it's covering €100,000 worth of training and type-ratings for these cadets out of it's own pockets. This is not a part sponsorship like other airlines offer where if you do the training they sorta kinda maybe might employ you at the end, this is the real deal.