Jack
I don't see what the issue is, your right has not being denied to strike. The union you pay to be repersented by screwed up big time on the balliout and breached existing agreements with the daa on industrail acrion. Think you need to take the issue up with them or join another union who woudn't screw it up.
It's sort of pointless now anyway as Ryanair and Aer Lingus are continuting with the revised schedule and most other airlines will probaly follow.
SIPTU will seek legal advice to develop strategy to "withdraw labour & take industrial action" if agreement can't be reached.