While that is definitely unfortunate, it looks like the system is working correctly. Aer Lingus is on the hook for millions of euros thanks to EU law, and then it goes after the IT provider to be made whole.
I guess let's wait to see how it works out in the US? The US government seems to be saying they're going to try to do something about this, so it doesn't seem like SWA is going to pay nothing here.
Actually, it appears that Southwest is already saying they'll reimburse tickets for canceled flights and potentially pay out for necessary hotels and alternate arrangements: https://www.southwest.com/html/air/travel-disruption
edit: though there is an extraordinary circumstances exception below. I'm not sure if this would qualify as that given that it's a combination of an adverse weather event and a technical system collapse.
