"Easy have a preference for the minimum appropriate fuel to be carried. If PLog fuel is deemed appropriate by the crew then that is what we carry. If more is thought to be required then it is put on and there are no questions asked. Period. Full stop. We are aware of both our responsibility to the company (to maximise potential profit) and the travelling public (to carry them in the safest possible way, which is our prime responsibility. Reference BRS airport!) and it shouldn't be a topic of public discussion in what is effectively an agony aunt forum".
This all sounds reasonable, and Easyjet has a good safety record. But I also think that many here are making assumptions that we simply don't know. But when an emergency is declared, whatever possible cause should be investigated and the cause determined. The crew obviously felt that it was necessary to declare an emergency. I would praise them for declaring it. That doesn't mean that they were at fault. But it doesn't mean that they weren't at fault either. There could have been a problem with the aircraft. Or they may have had bad information about something, such as the weather,or some other factor (ATC?) which may have led them into a decision of continuing on when perhaps they shouldn't have. Or, it might be that someone on the flight deck may have made a mistake. All of these things have happened before. There have been aircraft that departed without the minimum fuel required on the aircraft when the crew failed to check it. (US Air). There have been others that ran out of fuel in the air and either landed in an emergency or crashed. (Hapag Lloyd A310, Vienna, Swiss SAAB 2000 at Berlin, Air Transat A330 over the Atlantic).
We are all subject to human error and the system is also not perfect. But I think that all factors should be looked at and then a solid lesson can be learned.