The whole situation is a fine line. Look at one of the criteria that Ireland ran afoul of: "the basis of profit determination for companies in a multinational group departs from internationally accepted rules"

Which of course is amusing because there aren't really any internationally accepted rules. Companies like Apple e.g. Ikea, Coke, Google etc all do this and many countries allow it in particular the US.

I think it's fantastic that this precedent has been set. But it is a precedent none the less.