Not enough information here to form any conclusion. If the passengers were being kept on board for several hours without access to food and drink then I don't think survival is the issue - you just want to eat and drink. That being said, you'd have to buy it in for example the airport anyway (unless it's a meal voucher at the hotel etc). And it doesn't necessarily justify stealing it - the proper course would be a complaint but perhaps the passengers knew (or suspected) that Ryanair would tell them where to go.
From the story it doesn't look like Ryanair did anything wrong - you can't breach noise curfews except in an emergency. There has to be more to it. The Daily Mail is not known for forensic reporting.