I think the point people were trying to make was that Aer Lingus is more dependent on Ireland, where as it only represents a fraction of Ryanair's operations.
In other words, Ryanair could cut all routes from Ireland tomorrow and still be a fairly well functioning airline, if Aer Lingus on the other hand did that, they'd only have 2-3 charter routes on their books out of LGW, with no other routes to survive on.