Why do you think that the tie breakers are stupid ? FIFA uses the same rules but in a different order
First problem
IS the order. UEFA has it all wrong.
The next problem, and probably a bigger problem, is after goal differential comes total goals scored. Total goals against should always have more importance.
Had Italy won 2-0, as they did, but Spain and Croatia tied 1-1, they (Spain/Croatia) would have advanced. Spain due to goal differential (fair). Croatia due to more goals scored (wrong). Goal totals would have been Italy (4-2), Croatia (5-3). 4-2 is better than 5-3 every time. In fact, I'm pretty sure that is how UEFA sees it in the Champions League, so why the change for the Euro Cup?
Basically, it boils down to the fact Italy's 2-0 win against Ireland was a better result than Croatia's 3-1 win against Ireland. Somehow UEFA sees it opposite, that makes no sense.
Thankfully the point is moot though.