That's not the issue. Clearly they're doing that to make Dublin an international hub, especially onwards to the US. Whether Cork ever gets another Transatlantic flight is moot and not relevant, the key issue is the DAA have been pushing European flights, that should be out of Cork, to Dublin airport.
Cork is a second city of the EU and we have an appalling lack of flights to European airports. The best thing that could happen Cork is if the Greens and the nimbys keep opposing further Dublin Airport developments, to at least slow it down.