It's very simple as Capt Kremin points out.
Aer Lingus freely entered into agreements with the pilots regarding terms and conditions. Aer Lingus have unilaterally reneged on said agreements. Furthermore, they have rejected the pilots repeated offers to enter into negotiations. End of story.
Many are keen to portray it as "just another base" so what's the problem? No problem, the pilots are more keen than any management figure for a multitude of bases. Who do you think has more committment to a strong prosperous Aer Lingus, a transient management team or a lifer pilot?
But the dynamic is simple and the point is missed by most of our detractors. Let me spell it out:
BFS get paid less. The next base gets paid a bit less again, then the next (this pattern will sound familiar to ryanair pilots). Crews at cheaper bases will overnight in DUB and operate DUB routes. So DUB will stagnate. Bye bye command. Then along will come the management and say, sorry lads you cost more than all your colleagues, we'll have to pay you a lot less. Take it or leave it (sound familiar again, ryanair pilots?).
This industry is going down the tubes fast. Why? Because the utter apathy of most pilots allows management to walk all over us. Stand up people, get some backbone and improve your lot.
If we loose this situation, our careers will be gone to hell anyway, so may as well die fighting.
BTW, ryanair pilots. Why not join us on the picket line and together we can stop the rot destroying Irish aviation?