As Boy says, I think the reason people are happy to go back is because Aer Lingus did what it had to do at the time - without steps like that, there would be no Aer Lingus to go back to.
Aer Lingus even sold the art work that was contained with in it's head office as part of it's attempt to stay afloat - it wasn't like they made a casual desicion to just shrug off some staff, it really was a matter of life and death for Aer Lingus post September 11th.