Seems very normal to me.
Last month, I filed a complaint with A5 (Hop!). They used an online form as well. I got a response from them after 5 working days, telling me point black, that the EU regulation 261/04 did not stipulate any form of monetary compensation in case of a flight annulation.
Having complaints with airlines (especially if they are legally founded) are always a pain in the a.. . Usually you get a standard answer from a basic employee, who has absolutely no idea how the legal situation is and what exactly the ECJ ruled in the past. That is why I hate writing to the airlines.
So nothing, that is exclusive to Aer Lingus.